Changelog
A dated history of every calculator and guide added or updated on QuickCalc.ai, generated directly from each page's own "last updated" date.
October 30, 2026
The two rules that control which talents you can pick in a WoW Forever classic-style talent tree — row point thresholds and named prerequisites.
- CalculatorWoW Forever Talent Calculator
Plan a WoW Forever talent build for any of the 9 classes — click to allocate points across all three classic-style talent trees, hover any talent for its full description.
What changed: Talent data updated to the final WoW Forever beta build, 1.60.1.70634 (October 27, 2026). The trees show every talent as it stood when the beta closed: names, ranks, icons, positions, prerequisites, and rank 1 tooltip values, pulled from Wowhead's datamined beta data. Compared with the BlizzCon reveal build, 21 talents were added, 27 removed, and 164 changed. This is not yet live-game data. WoW Forever launches November 4, 2026, and launch-day hotfixes may change values.
How to plan a WoW Forever talent build, what each of a class's three classic-style talent trees covers, and where the data comes from.
October 23, 2026
- CalculatorBoard Foot Calculator
Figure board feet for any lumber size — 2x4, 2x6, 2x8, 2x10, 2x12 or a custom board — from length and quantity, convert linear feet to board feet, and estimate cost with waste.
- CalculatorCar Lease vs. Buy Calculator
Compare the net cost of leasing versus financing a car over your ownership period — including resale value, remaining loan balance, and total payments.
How many board feet are in a 2x4, 2x6, 2x8, 2x10 or 2x12, with a chart for 8, 10, 12 and 16 foot lengths.
How to calculate board feet from thickness, width and length, with worked examples for a single board and a full lumber order.
How to convert linear feet to board feet, and back, with the factor for each common lumber size and a worked example.
- CalculatorRent vs. Buy Calculator
Compare the financial outcome of renting versus buying a home over any time horizon — including home appreciation, mortgage interest, and the investment return on money not spent buying.
October 22, 2026
Sales tax worked out step by step: the same $100 purchase in six states, a discounted item, reversing a receipt total, and finding the rate you were charged.
- CalculatorPPC Calculator
Calculate CPC, CPM, and CTR from your ad spend, impressions, and clicks — plus optional conversion rate, CPA, and ROAS if you add conversions and revenue.
September 29, 2026
Whether switching a loan to biweekly payments actually saves meaningful interest, and when the difference is too small to bother with.
The exact formula lenders use to set a fixed loan payment, worked through with real numbers.
- CalculatorLoan Calculator
Estimate your payment, total interest, and payoff schedule for a personal, auto, student, or business loan — monthly, biweekly, or weekly.
How to read a loan calculator's payment, total interest, and total cost figures, and what an origination fee actually does to your loan.
September 15, 2026
How Mage and Shaman's WoW Forever talent trees differ in focus, for players deciding which class to plan a build around.
September 6, 2026
How the most common intermittent fasting protocols differ in eating window length, and what that practically means day to day.
- CalculatorBTU Calculator
Find the right air conditioner or heater size for a room from its area, sun exposure, occupants, and whether it's a kitchen.
How BTU sizing actually works for a room air conditioner or heater, why bigger isn't always better, and the standard sizing table behind the numbers.
The formula for figuring out how many gallons a trip will take from distance and fuel economy, with a reference table by vehicle type.
A quick reference for word count by speech length at common speaking paces, plus why real speeches usually run longer than the raw math.
- CalculatorIntermittent Fasting Calculator
Find your eating and fasting window times for 16:8, 18:6, 20:4, OMAD, or a custom schedule, based on when you eat your first meal.
How eating and fasting windows are calculated from your first meal time and chosen protocol, with a worked example on the 16:8 schedule.
- CalculatorRoad Trip Cost Calculator
Estimate total fuel cost for a road trip from distance, fuel economy, and gas price — plus cost per person if you're splitting it.
How to work out a road trip's total fuel cost from distance, fuel economy, and gas price, plus how splitting the cost between passengers works.
Why silent reading speed is so much faster than speech, and what that means for timing a script meant to be read aloud.
A few fair ways to split fuel cost between passengers on a road trip, and why splitting evenly isn't always the fairest option.
A quick reference for what size air conditioner fits common room sizes, and the factors that push the right size up or down.
How to pick a first-meal time that fits your schedule, and why the same protocol can look very different depending on when the window starts.
How an oversized air conditioner actually hurts comfort through short-cycling, and why matching BTU to the room beats rounding up.
- CalculatorWords to Minutes Calculator
Find how long a speech or reading will take from its word count and pace, or how many words fit in a set amount of time.
How to estimate speech or reading time from word count and pace, with reference words-per-minute rates for speaking and reading.
September 4, 2026
- CalculatorAmortization Calculator
See the full month-by-month payment schedule for any loan — how much of each payment goes to principal vs. interest, and how an extra payment shortens the payoff.
How a fixed loan payment splits between interest and principal over time, the formula behind it, and why an extra payment saves more early in a loan than late.
Why a longer loan term lowers the monthly payment but can more than double total interest paid, with a side-by-side example.
What each column of an amortization schedule actually means, and how to use it to check a lender's numbers or plan an extra payment.
September 2, 2026
The formula for marble countertop weight, a worked example at standard 3cm thickness, and why it matters for cabinets and moving day.
- CalculatorMarble Calculator
Estimate how much marble you need for a countertop, tile, or flooring project — square footage to order, weight, and cost.
How to work out how much marble to order for a countertop or tile project, why it weighs what it does, and where the standard 15% waste factor comes from.
How marble and granite countertops actually differ in durability, maintenance, and look, so you can compare them by more than price per square foot.
August 30, 2026
The difference between cost-per-click and cost-per-thousand-impressions pricing, and which one to focus on depending on your campaign's goal.
- CalculatorDog & Cat Age Calculator
Convert your dog's or cat's age into human-equivalent years using common veterinary aging guidelines, with size-based curves for dogs.
Why the old 'multiply by 7' dog-years rule is inaccurate, how size-based aging curves work, and how cat aging differs from dogs.
How dog and cat aging guidelines differ, including why dogs need size-based curves and cats generally don't.
The exact formula for click-through rate, a worked example, and why there's no single universal benchmark for what counts as a good CTR.
The size-based method for converting a dog's age into human-equivalent years, with a worked comparison across sizes.
A step-by-step worked example using the Devine formula, with a comparison across all four standard ideal body weight formulas.
A step-by-step worked example of the simple interest formula, plus how to solve for principal, rate, or time instead.
- CalculatorIdeal Body Weight Calculator
Estimate your ideal body weight range from height and sex using four standard clinical formulas (Devine, Robinson, Miller, Hamwi).
Where the Devine, Robinson, Miller, and Hamwi ideal body weight formulas came from, why they were designed for medical dosing, and how to interpret the range.
How ideal body weight formulas and BMI answer different questions, and why neither alone captures overall health.
- CalculatorSimple Interest Calculator
Calculate simple interest and total repayment from principal, rate, and time — or solve for any one of the four values.
How the simple interest formula works, how to rearrange it to solve for any variable, and where simple interest is actually used.
A direct numeric comparison of simple and compound interest on the same principal, rate, and term, and why the gap grows over time.
August 28, 2026
Beyond the net cost math, the practical tradeoffs between leasing and financing a car — mileage, flexibility, and long-term ownership.
- CalculatorDays Until Calculator (Countdown)
Count down the exact days, hours, minutes, and seconds until any date or holiday, with one-click presets for Christmas, New Year's, Halloween, and more.
How a live countdown calculator measures time to a target date, why it differs from a static date calculator, and how holiday presets stay accurate every year.
How next-occurrence holiday dates are calculated automatically, including the trickier case of Thanksgiving's floating date.
A step-by-step worked example calculating daily water intake needs from body weight, exercise, and climate.
The method for counting days until any future date, a worked example, and how to handle a date that has already passed.
Where the 8-glasses-a-day rule came from, why it doesn't fit everyone, and how to find a more individualized hydration target.
- CalculatorWater Intake Calculator
Estimate your recommended daily water intake from your body weight, exercise, and climate, shown in ounces, liters, cups, and 8-oz glasses.
How a weight-based water intake estimate is calculated, why exercise and climate matter, and how to tell if you're adequately hydrated.
August 24, 2026
How lenders calculate available home equity, how a HELOC's two payment phases work, and how it compares to a fixed home equity loan.
- CalculatorHome Equity Loan / HELOC Calculator
Find how much home equity you can borrow, then compare a fixed home equity loan's monthly payment against a HELOC's interest-only draw period and repayment-period payment.
The practical differences between a fixed home equity loan and a HELOC line of credit, and which situations favor each one.
A step-by-step worked example of the DIME method for estimating a life insurance coverage amount.
The combined loan-to-value formula lenders use to cap home equity borrowing, with a worked example.
The formula for running pace, a worked example, and how to convert between minutes-per-mile and minutes-per-kilometer.
How the DIME method estimates a life insurance coverage need, why each category matters, and what a general estimate can't account for.
- CalculatorLife Insurance Needs Calculator
Estimate how much life insurance coverage you need using the standard DIME method — debt, income replacement, mortgage payoff, and education costs, minus existing savings and coverage.
The math behind race time prediction from a known result, why the formula isn't linear, and how accurate it actually is.
- CalculatorRunning Pace Calculator
Find your running pace, total time, or distance from any two of the three, plus predicted race times at 5K, 10K, half marathon, and marathon distances.
How the pace-time-distance relationship works for runners, how race time predictions are calculated, and how to use both for training.
Why a coverage amount estimate like DIME doesn't tell you which type of life insurance to buy, and how term and permanent policies differ.
August 22, 2026
- CalculatorGarage Door Spring Calculator
Estimate the required torque, winding turns, and a suggested safe size range for torsion or extension garage door springs from your door's weight, height, and spring setup.
How garage door spring torque and winding turns are calculated, what the suggested wire size range actually means, and why safety comes before sizing.
The formula for garage door torsion spring torque, a worked example, and how drum diameter and spring count change the result.
The exact formula for a mortgage refinance break-even point, a worked example, and how rolling closing costs into the loan changes the math.
Is renting really throwing money away? The financial factors that decide whether renting or buying a house wins, and the one input that matters most.
- CalculatorRefinance Calculator
Compare your current mortgage to a new refinance offer — new monthly payment, break-even point on closing costs, and estimated lifetime interest savings.
How to read a refinance calculator's break-even point and lifetime savings figures, and what actually makes refinancing a mortgage pay off.
Comparing a mortgage refinance against simply paying extra toward your current loan's principal — which approach saves more interest, and when each makes sense.
How to tell torsion and extension garage door springs apart, how each is sized differently, and the specific safety hardware each one needs.
August 21, 2026
Why recurring meetings across time zones can silently shift by an hour around daylight saving transitions, and how to avoid it.
The correct way to convert a time between time zones, why a fixed offset table gets it wrong twice a year, and how to handle day-crossing conversions.
- CalculatorTime Zone Converter
Convert a time between cities worldwide with automatic daylight saving handling, or find a meeting time that works for everyone's business hours.
A complete overview of the Time Zone Converter — converting times across cities with automatic DST handling, and finding a shared meeting window.
August 20, 2026
Why payroll uses decimal hours instead of hours and minutes, and a quick conversion table for the most common minute values.
The difference between front-end and back-end debt-to-income ratios, why lenders check both, and which one usually ends up limiting a mortgage.
- CalculatorHouse Affordability Calculator
Find the maximum home price you can afford from your income, debts, and down payment — or work backward to find the income needed for a target home price.
A complete overview of the House Affordability Calculator — max home price, required income, DTI limits, and the full payment breakdown.
The exact formula for how long a retirement balance lasts at a given withdrawal rate, using inflation-adjusted returns, with a worked example.
The exact debt-to-income math lenders use to determine how much house you can afford, with a full worked example.
The exact math for turning clock-in and clock-out times into total hours worked, including unpaid breaks and overnight shifts.
The exact formula for net worth, what actually counts as an asset or liability, and the most common mistakes people make calculating it.
Representative median and average net worth figures by age bracket, and why the gap between the two numbers matters.
- CalculatorNet Worth Calculator
Add up your assets and liabilities to find your net worth, with a category breakdown and an optional comparison to your age group.
A complete overview of the Net Worth Calculator — itemized assets and liabilities, category breakdowns, and the optional age-group comparison.
- CalculatorRetirement Withdrawal Calculator
Find out how long your retirement savings will last at a given withdrawal amount, or the safe annual withdrawal for a target number of years.
A complete overview of the Retirement Withdrawal Calculator — how long savings last, the safe withdrawal for a target duration, and the 4% rule shortcut.
What the 4% retirement withdrawal rule actually says, where it comes from, and why a simple average-return calculator gives a different (usually longer) answer.
- CalculatorTime Card / Hours Calculator
Add up hours worked across multiple shifts from clock-in and clock-out times, subtract unpaid breaks, and estimate pay with optional overtime.
A complete overview of the Time Card / Hours Calculator — multi-shift totals, unpaid breaks, overnight shifts, and overtime pay estimation.
August 19, 2026
The exact formula for profit margin, worked examples at different price points, and how to find the price or cost needed to hit a target margin.
- CalculatorMargin / Markup Calculator
Find a sale price from cost and a target margin or markup, check both percentages from cost and price, or find the max cost you can pay for a target margin.
A complete overview of the Margin / Markup Calculator — pricing from cost, converting between margin and markup, and finding the max cost for a target margin.
Why a 50% markup is only a 33% margin, how to convert between the two, and which one to use for pricing vs. reporting.
August 17, 2026
- CalculatorDiscount / Sale Price Calculator
Find a sale price from one or more stacked discounts, work out what percent off a deal really is, or find the original price from a sale price.
A complete overview of the Discount / Sale Price Calculator — finding a sale price, checking the real percent off, reversing to the original price, and stacking discounts.
The exact math for finding a sale price from a discount, working out what percent off a deal really is, and reversing a sale price back to the original.
Why two stacked percentage discounts never add up to their sum, with worked examples showing the real combined discount at different sizes.
August 16, 2026
- CalculatorSales Tax Calculator
Add or reverse-calculate sales tax on any price — enter a rate directly or start from a U.S. state to auto-fill a representative rate.
A complete overview of the Sales Tax Calculator — adding tax, reverse-calculating a pre-tax price, and using representative state and local rates.
How tax-inclusive pricing (common outside the U.S.) and tax-exclusive pricing (the U.S. norm) differ, and how to convert a price between the two.
August 15, 2026
How 16-inch and 24-inch on-center stud spacing compare on stud count, lumber cost, load capacity, and drywall/sheathing compatibility.
How to calculate field studs, opening extras, and corner extras for a wall — the exact math behind a real stud count, not a rough guess.
A complete overview of everything the Wall Framing Stud & Plate Calculator computes — field studs, opening/corner extras, plates, and a board-foot piece list.
- CalculatorWall Framing Stud & Plate Calculator
Find how many studs and plates a wall needs from its length, height, on-center spacing, doors/windows, and corners — plus pre-cut lengths and a board-foot piece list.
August 11, 2026
A step-by-step framework for budgeting a home renovation from scope to financing to sequencing — how to get real material numbers, decide how to pay for it, and avoid the mid-project surprises that blow up budgets.
August 9, 2026
Check your Army Body Composition Program waist-to-height ratio against the 2026 ABCP standard — pass/fail status, max allowable waist, and margin to threshold.
How the Army's waist-to-height ratio standard differs from the older circumference-based body fat percentage method, and why WHtR uses one universal threshold instead of tables.
- CalculatorDebt Payoff Calculator
Find out how fast you can become debt-free using the avalanche or snowball method, with total interest paid and a month-by-month payoff order.
A side-by-side comparison of the debt snowball and avalanche payoff methods, with a worked example showing exactly how much each one costs in time and interest.
How much extra flooring to buy for straight, diagonal, and herringbone layouts, and why more complex patterns waste more material to angled cuts.
A plain-English breakdown of how 401(k) employer matching formulas work, why contributing less than the cap leaves money on the table, and how to calculate your total match.
The exact formula for calculating how many shingle bundles a roof needs, from footprint and pitch to squares to bundles, with a worked example.
How to estimate a realistic retirement savings target using your current age, contributions, employer match, and expected return, instead of a generic rule of thumb.
Why paying only the minimum on a credit card can take years and cost more in interest than the original balance, with the math behind why minimum payments are structured that way.
A combined formula for estimating both flooring and paint quantities for the same room, including how door and window openings factor into the wall calculation.
The exact formula for calculating Army waist-to-height ratio under the ABCP standard, including why it's truncated rather than rounded, with a worked example.
How the fertile window is calculated from your cycle length and luteal phase, why it's roughly 6 days long, and how to combine it with other fertility signals.
How roof pitch increases the real surface area you need to cover, how roofing squares work, and how to add a waste factor for shingles.
The correct waist measurement technique for the Army's waist-to-height ratio standard — location, posture, timing, and why averaging three readings matters.
The specific levers that actually shorten a debt payoff timeline — extra payments, interest rate, and payoff order — explained with the math behind each one.
Why calendar-based ovulation calculators are less reliable with irregular cycles, and which tracking methods work better when cycle length varies from month to month.
The difference between a materials waste percentage and a project contingency budget, and why a DIY renovation estimate needs both, not just one.
- CalculatorOvulation Calculator
Estimate your ovulation date and fertile window from your last period and average cycle length, with a 3-cycle forecast.
What an ovulation calculator's ovulation date and fertile window actually mean, how cycle length and luteal phase length change the result, and how accurate to expect it to be.
Project your retirement or 401(k) balance from your current savings, contributions, employer match, and expected return — and see if you're on track to hit your savings goal.
- CalculatorRoofing Calculator
Estimate roof area, shingle bundles, underlayment, and nails from your building footprint and roof pitch, with a cost estimate.
What each number in a roofing material estimate actually means — squares, bundles, underlayment, waste factor — and what a roofing quote typically adds on top.
Why roofers measure in "squares" instead of square feet, how to convert between the two, and why the roof surface is always larger than the building's footprint.
- CalculatorRoom / Project Material Estimator
Estimate flooring and paint or drywall materials for a whole room at once — boxes, gallons, sheets, cost range, and a shopping checklist, from one set of measurements.
The core tax difference between a Roth 401(k) and a traditional 401(k), how it affects your paycheck and retirement withdrawals, and how to think about which to choose.
August 8, 2026
- CalculatorGrade / Final Grade Calculator
Calculate your current course grade from weighted categories, solve for the score you need on a final exam, and send the result straight into the GPA Calculator.
How weighted-category grading actually works, why a blank score isn't the same as a zero, and how to solve for a course's overall grade by hand.
How many 90-minute sleep cycles map to a healthy night's sleep at every age, from newborns through older adults, with the reasoning behind each range.
- CalculatorSleep / Bedtime Calculator
Find the best bedtime or wake-up time based on complete 90-minute sleep cycles, with an age-based recommended sleep range and adjustable cycle length.
How sleep-cycle-based bedtime planning actually works, why waking mid-cycle causes grogginess, and how to use cycle counts instead of raw hours to plan your sleep.
The exact formula for working out what score you need on a final exam to hit a target course grade, with a worked example and what to do if the target isn't reachable.
Getting a full 8 hours but still waking up groggy usually comes down to where in your sleep cycle the alarm lands — here's the explanation and how to fix it.
August 7, 2026
- CalculatorGPA Calculator
Calculate your semester and cumulative GPA from your courses, credit hours, and grades — with weighted Honors/AP support and a target-GPA planner.
How GPA is actually calculated from grade points and credit hours, why it's a weighted average and not a simple one, and how to combine a new semester with your cumulative GPA.
Weighted and unweighted GPA can differ by a full point or more for the same transcript — here's exactly how the bonus points work and why colleges often recalculate both.
How to work backward from a GPA goal to figure out what average grade you need across your remaining credits — with the formula and a worked example.
August 6, 2026
- CalculatorCurrency Converter
Convert between 30 major currencies instantly with live, daily-updated exchange rates from the European Central Bank.
How live currency conversion actually works, why the rate you see online rarely matches what your bank charges, and how to convert money accurately for travel or shopping.
A practical way to turn a foreign daily budget into your home currency, account for card fees and exchange markup, and avoid the most common travel-money mistakes.
The mid-market exchange rate and the rate your bank actually gives you are rarely the same number — here's why, how big the gap usually is, and how to estimate what you'll really pay.
August 3, 2026
- CalculatorDrywall Calculator
Find how many drywall sheets you need from your room dimensions and door/window openings, plus joint compound, tape, screws, and cost.
A complete overview of everything a drywall job needs — sheets, joint compound, tape, and screws — and how each quantity is calculated.
How 4×8, 4×10, and 4×12 drywall sheets compare on coverage, seam count, weight, and when each size actually makes sense.
How to figure out exactly how many pavers a patio needs, why laying pattern changes the waste factor, and how paver size affects the count.
How to figure out exactly how many sheets of drywall a room needs, why door and window deductions matter, and how sheet size changes the count.
The exact formulas for calculating square footage of rectangular, L-shaped, circular, and triangular rooms, with worked examples for each.
A step-by-step method for measuring an L-shaped room accurately, including which dimensions to take and the subtraction formula that turns them into square footage.
- CalculatorPaver / Patio Calculator
Find how many pavers your patio needs from its dimensions and paver size, plus compacted base, sand, edging, and jointing sand, with cost.
The difference between the compacted base and the sand setting bed under a paver patio, why both matter, and what happens if you skip one.
Why polymeric sand is the standard choice for filling paver joints over regular jointing sand, how it works, and how much you'll need.
How square feet, square yards, and square meters relate to each other, the exact conversion factors, and which one each trade typically uses.
- CalculatorSquare Footage / Area Calculator
Find the square footage of a rectangle, L-shape, circle, or triangle, and total multiple rooms at once, in sq ft, sq m, or sq yd, with cost.
August 1, 2026
- CalculatorAge Calculator
Find your exact age in years, months, and days, plus your birth day of the week and next birthday countdown.
- CalculatorBMI Calculator
Calculate your Body Mass Index and healthy weight range using metric or imperial units.
- CalculatorConcrete, Mulch & Topsoil Calculator
Estimate cubic yards, bags needed, and cost for concrete, mulch, or topsoil in any rectangular or circular area.
- CalculatorDate Calculator
Find the exact number of days, weeks, or months between any two dates, plus a business-day count.
- CalculatorFlooring Calculator
Estimate how many boxes of tile, hardwood, or laminate flooring you need for any room, with cost estimates.
How kilobytes, megabytes, gigabytes, and terabytes relate to each other, why 1,024 rather than 1,000 is used in computing, and why a drive's usable space looks smaller than advertised.
The exact formula for converting Celsius to Fahrenheit and back, why temperature conversion needs an offset instead of just a multiplier, and worked examples.
The exact kilogram-to-pound conversion factor, a quick reference table for common weights, and a fast mental-math estimate.
How meters and feet relate, the exact conversion factor, quick mental-math shortcuts, and when precision actually matters.
- CalculatorPaint Calculator
Estimate how much paint and how many gallons or liters you need for any room, with cost estimates.
- CalculatorUnit Converter
Convert length, weight, volume, temperature, area, speed, time, data storage, pressure, energy, and angle units instantly, with formulas shown.
July 31, 2026
- CalculatorAuto Loan Calculator
Calculate your monthly car payment, total interest, and total cost from a vehicle price, down payment, trade-in, sales tax, rate, and loan term.
The exact formula behind a car payment, how trade-ins and sales tax factor in, and a full worked example from vehicle price to monthly payment.
- CalculatorCompound Interest Calculator
Calculate the future value of an investment from a principal, interest rate, compounding frequency, time, and optional monthly contributions.
The compound interest formula broken down piece by piece, with a full worked example and a direct comparison against simple interest.
- CalculatorDue Date Calculator
Estimate your pregnancy due date and current gestational age from your last period, conception date, or IVF transfer date, with key trimester milestones.
The three ways to calculate a pregnancy due date — last period, conception date, and IVF transfer — with the exact formulas and worked examples for each.
A side-by-side comparison of 36, 48, 60, and 72 month auto loan terms on the same loan amount, and why a longer term costs much more in total interest.
How gestational age is counted in weeks and days from your last period, why it starts before conception, and how to calculate it yourself.
Why starting to invest early beats contributing more money later, with a full worked comparison of two savers at different starting ages.
Rules of thumb for setting a car budget, how down payment and trade-in change what you can afford, and a worked comparison of a new vs. used car payment.
Why increasing your 401(k) contribution costs you less take-home pay than the dollar amount you contribute, with a worked before-and-after example.
How last-period dating and early ultrasound dating can produce different due dates, and why doctors often adjust to whichever is more reliable for your situation.
- CalculatorPaycheck Calculator
Estimate your take-home pay after federal tax, state tax, and FICA from your salary or hourly wage, pay frequency, filing status, and state.
The exact order taxes come out of a paycheck — pre-tax deductions, federal tax, FICA, and state tax — with a full worked example from gross to net.
How to convert an hourly wage to an annual figure for tax purposes, and a worked example comparing hourly and salaried take-home pay.
How the Rule of 72 works, how accurate it really is compared to the exact compound interest formula, and worked examples at several interest rates.
July 30, 2026
A side-by-side comparison of 15-year and 30-year mortgage terms on the same loan amount — monthly payment, total interest, and which one actually fits your budget.
How adding even a small extra amount to your monthly mortgage payment cuts years off your loan and saves tens of thousands in interest, with a full worked example.
- CalculatorMortgage Calculator
Calculate your monthly mortgage payment, total interest, and payoff timeline — with optional property tax, insurance, PMI, HOA, and extra payments.
The exact amortization formula behind every mortgage payment, a full worked example, and how PITI (principal, interest, taxes, insurance) changes what you actually owe each month.
July 29, 2026
Standard tip percentages for restaurants, delivery, bars, salons, and rideshares, and how to adjust for service quality.
The exact formula for percent change, why order and direction matter, and worked examples covering raises, price hikes, discounts, and investment losses.
Why 'a 3% rise' and 'a 3 percentage point rise' mean very different things, with examples from interest rates, tax brackets, and poll numbers.
- CalculatorPercentage Calculator
Find what X% of a number is, what percent one number is of another, percent change between two values, or the whole from a known part.
The four percentage formulas you'll actually use — finding a part, finding a percent, percent change, and reversing a percentage — each with worked examples.
The tradeoffs between splitting a group bill evenly and splitting it by what each person actually ordered, with examples of when each approach makes sense.
- CalculatorTip Calculator
Calculate the tip and total for any bill, and split it evenly between any number of people.
The exact formula for calculating a tip and splitting a bill evenly, with worked examples for solo diners, couples, and larger groups.
July 28, 2026
- CalculatorBody Fat Calculator
Estimate your body fat percentage using the U.S. Navy method or BMI method, plus fat mass, lean mass, and your ideal healthy range.
What each result from the body fat calculator means — fat mass, lean body mass, category, and ideal range — and how to use them to set a real target.
How body fat percentage and BMI differ, why they can disagree for the same person, and when each measurement is actually the more useful one.
Step-by-step guide to the U.S. Navy body fat formula, how to measure neck, waist, and hip correctly, and why it beats BMI for estimating body composition.
Step-by-step math for laying out a stair stringer: finding total rise, riser height, tread depth, and stringer length before you cut a single board.
- CalculatorStair Calculator
Find the number of steps, riser height, tread depth, stringer length, and stair angle from your total rise — with IRC code-compliance checks.
Why riser height and tread depth trade off against each other, the rule of thumb builders use to balance them, and what building code requires.
July 27, 2026
How BMI is calculated, what the standard weight categories mean, and the real limitations of BMI as a health measurement.
The difference between Basal Metabolic Rate and Total Daily Energy Expenditure, how activity multipliers work, and which number to actually eat to.
- CalculatorCalorie Calculator (TDEE & BMR)
Find your BMR, TDEE, and daily calorie target for weight loss, maintenance, or muscle gain, with an optional macro breakdown.
How composite and pressure-treated wood decking compare on cost, lifespan, and maintenance, and how board width affects your material count.
A side-by-side comparison of concrete and gravel driveways on cost, durability, drainage, and maintenance to help you decide which fits your project.
A complete overview of everything a deck build needs — boards, joists, screws, and footing concrete — and how each is calculated.
How to decide whether to calculate your fence project by prefab panels or by linear feet of continuous material, with examples of each.
How a healthy weight range is derived from the BMI 18.5–24.9 band for any given height, with example ranges and important caveats.
How to find your daily calorie target for weight loss using TDEE and a calorie deficit, with realistic rates of loss and why crash diets backfire.
When one coat is enough, when you need two or three, and how primer changes the calculation for a repaint or color change.
How to calculate fence post count including line posts, corner posts, and gate posts, plus typical spacing and concrete footing guidance.
How to measure a room for flooring, why box coverage numbers vary, and how much extra to order so you don't run short mid-install.
How gravel driveways are built in layers, how much depth and tonnage each layer needs, and how to calculate the total material cost.
Why every material estimate needs a waste factor, and typical waste percentages for gravel, concrete, mulch, and deck material projects.
The cubic-yard formula for a concrete slab, standard thickness by use case, and how to convert your total into bag count or a ready-mix order.
How to manually count the days between two dates, why calendar month lengths and leap years complicate it, and common real-world uses.
The correct way to calculate exact age accounting for leap years and varying month lengths, and why simple year subtraction gets it wrong.
How business-day counting differs from calendar-day counting, why weekends are excluded, and where holidays fit into the calculation.
A step-by-step method for measuring your roof's rise and run safely from the attic, plus how to read the result as a standard pitch ratio.
How deep to mulch a flower bed, how to measure irregular bed shapes, and how to decide between bagged and bulk mulch.
How to figure out exactly how much paint a room needs, why coverage estimates go wrong, and how coats, primer, and wall texture change the math.
How Palworld's hidden breeding power system determines offspring, including the standard averaging formula and special fixed combinations.
How Palworld's mutation system picks which Pal a mutated egg hatches, and how to raise your odds of a specific, targeted mutation.
The real differences between pea gravel and crushed stone — shape, drainage, stability, and which projects each one actually fits.
Why tile and hardwood need different waste factors and how box sizes, cut patterns, and material cost compare between the two.
How generational cohorts like Millennial, Gen X, and Gen Z are defined by birth year, and where those date ranges actually come from.
July 26, 2026
- CalculatorDeck Material Calculator
Find how many deck boards, joists, screws, and footing concrete bags you need from your deck's dimensions, board size, and layout — plus cost.
- CalculatorFence Calculator
Find how many fence panels or posts you need from your fence length, gates, and spacing — calculate by panels or by linear feet, plus cost.
- CalculatorGravel Calculator
Get cubic yards, tons, and cost for driveways, paths, and drainage — includes pea gravel, crushed stone, sand, and river rock.
- CalculatorPalworld Breeding Calculator
Find the exact offspring of any two Pals, work backward from a target Pal, or see every mutated egg outcome — all 299 Pals.
- CalculatorRoof Pitch Calculator
Find your roof's pitch ratio, angle in degrees, and slope percentage from rise and run, plus rafter length and roof area.