Square Footage / Area Calculator
Find the area of a rectangle, L-shape, circle, or triangle, and total multiple rooms at once — in sq ft, sq m, or sq yd, with cost.
How to use the area calculator
- 1
Pick a shape for your first area: Rectangle, L-shape, Circle, or Triangle.
- 2
Enter its dimensions — each shape shows only the fields it needs.
- 3
Click "Add another area" for each additional room or space — the total updates automatically with a full breakdown.
- 4
Choose sq ft, sq m, or sq yd for your results, and optionally add a waste factor and price to estimate cost.
Area formulas, with examples
1. Rectangle
Formula: length × width
Example: A 14 ft × 11 ft bedroom is 14 × 11 = 154 sq ft.
2. L-shape
Formula: (outer length × outer width) − (cutout length × cutout width)
Example: A room measures 16 ft × 12 ft overall, but a 5 ft × 4 ft corner is missing (say, for a closet that juts into the space). Area = (16 × 12) − (5 × 4) = 192 − 20 = 172 sq ft.
3. Circle
Formula: π × radius² (radius = diameter ÷ 2)
Example: A circular patio 12 ft across (diameter) has a radius of 6 ft. Area = π × 6² = π × 36 ≈ 113.1 sq ft.
4. Triangle
Formula: (base × height) ÷ 2
Example: A triangular flower bed with a 10 ft base and a 6 ft height is (10 × 6) ÷ 2 = 60 ÷ 2 = 30 sq ft.
5. Multi-room total
Formula: sum of every individual area
Example: A 154 sq ft bedroom plus a 172 sq ft L-shaped living room plus a 60 sq ft closet totals 154 + 172 + 60 = 386 sq ft — exactly what this calculator does automatically when you add multiple areas.
Sq ft vs. sq m vs. sq yd
| 1 unit | Equals | Commonly used for |
|---|---|---|
| 1 sq ft | 0.111 sq yd, 0.0929 sq m | US flooring, paint, drywall, real estate listings |
| 1 sq yd | 9 sq ft, 0.836 sq m | Carpet pricing, landscaping fabric |
| 1 sq m | 10.764 sq ft, 1.196 sq yd | Everywhere outside the US |
Need to convert a single value between other units too — like inches to centimeters, or pounds to kilograms? The Unit Converter covers length, weight, volume, and more.
What to do with your square footage
Once you have an accurate total, plug it straight into a material-specific calculator to turn square footage into an actual shopping list:
- Painting a room? The Paint Calculator converts wall area into gallons or liters needed.
- New flooring? The Flooring Calculator turns floor area into the number of boxes to buy.
- Hanging drywall? The Drywall Calculator converts wall (and ceiling) area into sheet count, plus joint compound, tape, and screws.
- Building a patio? The Paver / Patio Calculator turns patio area into paver count, base material, and sand.
Since every one of those calculators includes its own length × width inputs, this Area Calculator is most useful up front — for irregular L-shaped rooms, circular spaces, triangular areas, or adding up several rooms before you start shopping for material.
Frequently asked questions
Related guides
The exact formulas for calculating square footage of rectangular, L-shaped, circular, and triangular rooms, with worked examples for each.
Read the guide →How square feet, square yards, and square meters relate to each other, the exact conversion factors, and which one each trade typically uses.
Read the guide →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.
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