What is square footage?
Square footage is the area of a flat surface measured in square feet (sq ft). It is the number you need for almost every home project: buying flooring, carpet, tile or sod, estimating paint, comparing home prices and getting contractor quotes, which are usually priced per square foot.
This sqft calculator works for rectangles, circles and triangles. For irregular rooms, split the space into simple shapes, calculate each one and add the results. You can enter measurements in feet, inches, yards, meters or centimeters, and the result is shown in square feet, square meters, square yards and acres.
How to use this sqft calculator
- Choose the shape of the area.
- Measure the length and width (for a circle, the diameter; for a triangle, the base and height).
- For L-shaped or irregular rooms, split them into simple shapes and add the results.
- Optionally enter a price per square foot to estimate material or labor cost.
Example
A 14 × 12 ft bedroom has an area of 168 sq ft. That is 15.61 m² or 18.67 sq yd. If the flooring you like costs $3.50 per square foot, the material alone comes to about $588, before adding 10% extra for cuts.
What to know before you buy
Square feet, square meters and square yards
In the US and Canada, floor area is usually quoted in square feet, while most other countries use square meters. One square meter equals 10.764 square feet, so a 20 m² room is about 215 sq ft. Carpet is sometimes still sold by the square yard (9 sq ft), and land by the acre (43,560 sq ft).
Measuring a whole house
To find the square footage of a house, measure the exterior walls of each floor and multiply length by width, section by section. Appraisers normally count only finished, heated living space: garages, unfinished basements and porches are listed separately.
Square footage of common room sizes
| Room size | Area | Square meters |
|---|---|---|
| 10 × 10 ft | 100 sq ft | 9.29 m² |
| 10 × 12 ft | 120 sq ft | 11.15 m² |
| 12 × 12 ft | 144 sq ft | 13.38 m² |
| 12 × 15 ft | 180 sq ft | 16.72 m² |
| 14 × 16 ft | 224 sq ft | 20.81 m² |
| 15 × 20 ft | 300 sq ft | 27.87 m² |
| 20 × 20 ft | 400 sq ft | 37.16 m² |
| 24 × 24 ft (2-car garage) | 576 sq ft | 53.51 m² |
Formula
Rectangle: length × width. Circle: π × (diameter ÷ 2)². Triangle: base × height ÷ 2. 1 square yard = 9 sq ft, 1 m² = 10.764 sq ft, 1 acre = 43,560 sq ft.
Tips from the pros
- Measure wall to wall at floor level, and round each measurement up to the nearest inch.
- For an L-shaped room, split it into two rectangles; for a room with a bay window, add the bay as a separate rectangle or triangle.
- To convert inches to feet, divide by 12: 8 ft 6 in is 8.5 ft. Or simply choose inches as the unit and let the calculator convert.
- Buy 5–10% more material than the square footage for flooring and tile, and 10–15% for diagonal layouts.
Common mistakes to avoid
- Multiplying feet by inches: always use the same unit for length and width.
- Confusing square feet with linear feet. Baseboard and trim are sold by the linear foot, flooring by the square foot.
- Using the home's listed square footage for a single room project: listings include walls, closets and stairs.
Frequently asked questions
How do I calculate square footage?
Multiply length by width in feet. A 12 × 10 ft room is 120 square feet.
How do I measure an L-shaped room?
Divide it into two rectangles, calculate each area and add them together.
How many square feet are in a square meter?
1 square meter equals about 10.764 square feet.
How do I convert square feet to acres?
Divide by 43,560. For example, 10,000 sq ft is about 0.23 acres.
How many square feet is a 12x12 room?
144 square feet (12 × 12).
How do I calculate the square footage of a circle?
Multiply π (3.1416) by the radius squared. A circle 10 ft across has a radius of 5 ft, so its area is about 78.5 sq ft.