Square Footage and Area Calculator
Calculate square footage and area for rooms, floors and lots. Add rectangles, circles and triangles, subtract openings and get sq ft, sq m, sq yd and acres.
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Add each room or section, pick a shape and enter its dimensions. The total updates in square feet, square meters, square yards and acres.
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Square footage and area calculator
This calculator finds the area of any space by combining simple shapes. It works as a square footage calculator for rooms, floors, walls, lots and gardens, and it also gives the result in square meters, square yards and acres. Add as many sections as you need, subtract openings or excluded areas, and add a waste percentage and a price per square foot to estimate material cost.
Area formulas
- Rectangle or square: length × width
- Circle: π × radius²
- Triangle: ½ × base × height
- Trapezoid: ½ × (base 1 + base 2) × height
Useful conversions
| Unit | Equals |
|---|---|
| 1 square meter | 10.764 square feet |
| 1 square yard | 9 square feet |
| 1 acre | 43,560 square feet |
| 1 square foot | 0.0929 square meters |
Example: flooring a room
A living room measures 15 ft by 12 ft, which is 180 sq ft. Add a 10 percent waste allowance for cuts and you need about 198 sq ft of material. At 4.50 per square foot, the estimated cost is 891.00. Use the optional fields above to run your own numbers.
How to use the area calculator
- Pick the measuring unit, such as feet or meters.
- Choose a shape for each section and enter its dimensions. Add more sections for other rooms or parts.
- Optionally enter a waste percentage and a cost per square foot, then press Calculate area.
Frequently asked questions
How do you calculate square footage?
For a rectangle or square room, multiply length by width in feet. For example, a room 12 ft by 10 ft is 120 square feet. For irregular rooms, split the space into rectangles, triangles or circles, calculate each one and add them together.
How do I convert square feet to square meters?
Multiply square feet by 0.0929 to get square meters. For example, 120 sq ft is about 11.15 sq m. To go the other way, multiply square meters by 10.764.
How many square feet are in an acre?
One acre is 43,560 square feet. The calculator shows the total in acres automatically.
How much extra material should I buy for flooring or paint?
A common rule is to add 5 to 10 percent for waste, cuts and mistakes, and more for diagonal layouts or patterned materials. Enter that percentage in the waste field to see the adjusted total.
How do I measure an L-shaped room?
Split it into two rectangles, measure each one and add both areas with the Add another section button. If part of the room is not included, add it and tick the subtract box.
Are the data I enter saved?
No. The calculation runs in your browser and nothing is sent to a server.