Home › Measurement › Square Footage Calculator
This square footage calculator finds the area of a room, yard, lot or any surface in square feet, square yards, square meters and acres. Choose a rectangle, circle, triangle or trapezoid, enter your measurements in feet or meters, and add a price per square foot to estimate the cost of materials or services.
How to Use the Square Footage Calculator
- Choose the shape that best matches the area.
- Enter the measurements in feet or meters (switch units at the top).
- If you have several identical areas, such as three bedrooms of the same size, enter the number of areas.
- Optionally enter a price per square foot or square meter to estimate the cost.
Square Footage Formulas
| Shape | Formula |
|---|---|
| Rectangle or square | Length × Width |
| Circle | π × (Diameter ÷ 2)² |
| Triangle | ½ × Base × Height |
| Trapezoid | (Side a + Side b) ÷ 2 × Height |
All measurements must be in the same unit. If you measured in inches, divide by 12 to get feet before multiplying, or divide the result in square inches by 144.
Worked Examples
- A 12 × 10 ft bedroom: 12 × 10 = 120 sq ft, which is 13.3 sq yd or 11.15 m².
- A round patio 10 ft across: 3.1416 × 5 × 5 = 78.5 sq ft.
- A trapezoid-shaped garden bed with parallel sides of 6 ft and 10 ft, 8 ft apart: (6 + 10) ÷ 2 × 8 = 64 sq ft.
How to Measure an Irregular Room
Split L-shaped rooms, open-plan spaces and odd-shaped yards into rectangles, triangles and circles. Calculate each piece separately and add them together. Subtract any area you will not cover, such as a kitchen island or a built-in cabinet.
Area Unit Conversions
| Unit | Equals |
|---|---|
| 1 square foot | 144 sq in = 0.0929 m² |
| 1 square yard | 9 sq ft = 0.836 m² |
| 1 square meter | 10.764 sq ft = 1.196 sq yd |
| 1 acre | 43,560 sq ft = 4,046.9 m² |
| 1 hectare | 10,000 m² = 2.471 acres |
What Square Footage Is Used For
- Ordering flooring, tile or carpet; see our flooring calculator for box counts.
- Estimating paint for walls with our paint calculator.
- Pricing sod, mulch or gravel for a yard with the sod calculator.
- Comparing home prices and rents per square foot.
Frequently Asked Questions
How do I calculate square footage?
Multiply the length by the width in feet. For other shapes, use the matching formula: π × radius² for circles, ½ × base × height for triangles.
How many square feet is a 12×12 room?
A 12 × 12 ft room is 144 square feet, which equals 16 square yards or about 13.4 square meters.
How do I convert square feet to square meters?
Multiply square feet by 0.0929, or divide by 10.764. For example, 200 sq ft is about 18.6 m².
How many square feet are in an acre?
One acre is 43,560 square feet, or about 4,047 square meters.
How do I find the square footage of an L-shaped room?
Split the room into two rectangles, calculate the area of each, and add them together.
Read the guide: How to Calculate Square Footage (With Examples)
Related Calculators
Browse all measurement calculators or see every tool on our home page.