How accurate is this unit converter?

It uses exact, standards-defined conversion factors wherever one exists — for example 1 inch = 2.54 cm exactly, and 1 pound = 0.45359237 kg exactly, both by international definition. Results are computed in full floating-point precision and only rounded for display, so the underlying math is as accurate as your browser's arithmetic.

Why does temperature conversion work differently from the others?

Length, weight, and most other units convert with a simple multiplication (1 inch is always 2.54 cm, no matter the value). Temperature scales don't share a common zero point, so converting requires an offset as well as a scale factor — for example °F = (°C × 9/5) + 32. That's why 0°C converts to 32°F rather than 0°F.

What does the 'Data' category use for kilobytes and gigabytes?

This converter uses the binary convention common in computing and operating systems: 1 KB = 1,024 bytes, 1 MB = 1,024 KB, and so on. Some contexts (like hard drive marketing or the SI standard) use 1,000-based decimal units instead, which is one reason a drive's actual usable space often looks smaller than its labeled size.

Is my data sent anywhere when I use this converter?

No. Every conversion runs locally in your browser using JavaScript — nothing you type is transmitted to a server, logged, or stored. You can use it fully offline once the page has loaded.

Why does my result show scientific notation?

Extremely large or small results (for example converting a few bytes into petabytes) switch to scientific notation (like 4.6e-13) so the number stays readable instead of showing a long string of leading or trailing zeros. Everyday conversions display as normal decimal numbers.

Which gallon, ounce, and ton does this converter use?

Volume conversions use the US customary gallon, fluid ounce, cup, pint, and quart (not the UK imperial versions, which are about 20% larger for gallons). Weight conversions use the US short ton (2,000 lb) rather than the UK long ton (2,240 lb).

Can I convert in reverse without retyping everything?

Yes — tap the swap button between the From and To fields. It flips the two units and carries your current result over as the new starting value, so you can bounce back and forth between two units without re-entering numbers.

Unit Converter

Convert length, weight, volume, temperature, area, speed, time, data storage, pressure, energy, and angle units instantly, with the formula shown.

From

2.54

Quick conversions

Formula

1 in = 2.54 cm

How to use the unit converter

1
Pick a category tab — Length, Weight, Volume, Temperature, Area, Speed, Time, Data, Pressure, Energy, or Angle.
2
Type a value in the From field and choose your From and To units from the dropdowns.
3
Your converted result updates instantly as you type — no button to click. Use the swap button to reverse the conversion, or tap a quick-conversion chip for a common pairing.

How unit conversion works

Every conversion routes through a common base unit for that category — the From value converts into the base unit, then out into the To unit.

Most unit conversions are a single multiplication: to convert a value, multiply it by a fixed factor. Internally, this calculator converts your From value into a shared base unit for that category (meters for length, kilograms for weight, and so on), then converts that base value into your target unit. This two-step approach means adding a new unit only requires knowing its relationship to the base unit, not to every other unit in the category.

Temperature is the exception. Celsius, Fahrenheit, and Kelvin don't share a common zero point, so converting between them requires an offset in addition to a scale factor — for example, 0°C is 32°F, not 0°F. The formula card below the calculator updates to show the exact formula for whatever conversion you have selected.

Where an exact, standards-defined value exists, this calculator uses it rather than a rounded approximation — for example 1 inch = 2.54 cm and 1 pound = 0.45359237 kg are both exact by international definition, not rounded figures.

Supported categories and units

Category	Units included
Length	mm, cm, m, km, in, ft, yd, mi
Weight	mg, g, kg, metric ton, oz, lb, stone, US ton
Volume	mL, L, m³, tsp, tbsp, fl oz, cup, pint, quart, gallon (US)
Temperature	Celsius, Fahrenheit, Kelvin
Area	mm², cm², m², hectare, km², in², ft², yd², acre, mi²
Speed	m/s, km/h, mph, knot, ft/s
Time	ms, sec, min, hr, day, week, month, year
Data	bit, byte, KB, MB, GB, TB, PB (1,024-based)
Pressure	Pa, kPa, bar, atm, psi, mmHg, torr
Energy	J, kJ, cal, kcal, Wh, kWh, BTU
Angle	degree, radian, gradian, arcminute, arcsecond, turn

Everyday uses for unit conversion

Cooking and recipes: converting between cups, tablespoons, and milliliters is essential when following a recipe written for a different measurement system, or scaling a recipe up or down.

Travel and weather: checking a forecast in Celsius when you think in Fahrenheit, or converting kilometers to miles to gauge a driving distance in an unfamiliar country.

Fitness and health: converting body weight between kilograms and pounds, or a running pace between km/h and mph. Our BMI Calculator handles both metric and imperial input directly if you need a health-specific result rather than a raw conversion.

Home and construction projects: converting square footage to square meters, or checking a material quantity given in an unfamiliar unit. Our Flooring Calculator and Concrete, Mulch & Topsoil Calculator can take it from there once you have your area in the right unit.

Tech and storage: figuring out how many GB fit in a TB drive, or converting a file size between MB and GB before an upload limit.

Need a quick percentage instead of a unit conversion? Try the Percentage Calculator →

Frequently asked questions

The exact formula for converting Celsius to Fahrenheit and back, why temperature conversion needs an offset instead of just a multiplier, and worked examples.

Read the guide →

Meters vs. Feet: Converting Between Metric and Imperial Length

How meters and feet relate, the exact conversion factor, quick mental-math shortcuts, and when precision actually matters.

Read the guide →

Kg to Lbs: How to Convert Kilograms to Pounds

The exact kilogram-to-pound conversion factor, a quick reference table for common weights, and a fast mental-math estimate.

Read the guide →

GB vs. MB vs. KB: How Data Storage Units Actually Work

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.

Read the guide →