About the Square Footage calculator
This square footage calculator finds the floor area of a room, or adds up up to three rooms, from their length and width in feet. Use it when you're buying flooring, carpet or tile, estimating a renovation, comparing listings, or working out how much space you really have.
The total is shown in square feet, square meters and square yards, since carpet is often sold by the square yard. Add a price per square foot and the calculator also gives you the total cost.
How to use it
- Enter Room 1 length and Room 1 width in feet.
- To include more rooms, fill in Room 2 length, Room 2 width, Room 3 length and Room 3 width. Leave them blank otherwise.
- Optionally enter a Cost per sq ft (optional) for materials or labor.
- Read the total area in square feet, square meters and square yards, and the total cost.
The formula
Each room is treated as a rectangle:
area = length × widthtotal = room 1 + room 2 + room 3
- Square meters = square feet × 0.09290304.
- Square yards = square feet ÷ 9, because a yard is 3 feet and 3 × 3 = 9.
- Total cost = total square feet × cost per square foot.
- A room is only counted when both its length and width are filled in.
Lengths are in decimal feet. To enter feet and inches, divide the inches by 12 and add them: 12 ft 6 in is 12.5 ft.
Worked example
A bedroom is 12 ft × 14 ft and an office is 10 ft × 11 ft.
- Bedroom: 12 × 14 = 168 sq ft
- Office: 10 × 11 = 110 sq ft
- Total: 278 sq ft, which is 25.83 m² or 30.89 sq yd
If flooring costs, for example, $5 per square foot installed, the total is 278 × $5 = $1,390. Many installers suggest buying 5% to 10% extra to cover cuts and mistakes, so you might plan for about 300 sq ft of material.
Odd shapes and inches
L-shaped rooms. Split the room into two rectangles, measure each one, and enter them as Room 1 and Room 2. The total is the area of the whole L. For a room with a bay or closet, add it as a separate small rectangle.
Subtracting. To leave out something like a kitchen island, work out its area separately and subtract it from the total.
Inches to decimal feet:
| Inches | Feet |
|---|---|
| 1 in | 0.083 ft |
| 3 in | 0.25 ft |
| 4 in | 0.333 ft |
| 6 in | 0.5 ft |
| 8 in | 0.667 ft |
| 9 in | 0.75 ft |
For triangles, circles and other shapes, the area calculator has the formulas. To change units, try the area converter, and to paint the same room, the paint calculator.
Frequently asked questions
How do I calculate the square footage of a room?
Measure the length and width in feet and multiply them. A 12 ft × 15 ft room is 180 square feet.
How do I measure an L-shaped room?
Divide it into two rectangles, find the area of each, and add them together. Enter them here as two rooms.
How many square feet are in a square yard?
There are 9 square feet in a square yard, because a yard is 3 feet on each side.
How do I convert square feet to square meters?
Multiply by 0.09290304. So 200 sq ft is about 18.58 m².
How much extra flooring should I buy?
Buying 5% to 10% extra is common practice to allow for cuts and waste, and more for diagonal layouts or patterned tile.
Last updated October 24, 2026. Results are estimates for education and planning — see our disclaimer.