Square Footage Calculator
Add up the area of any space — even L-shaped rooms and irregular yards — by combining simple shapes. Results in square feet, square yards, square meters and acres.
Enter the dimensions of at least one area.
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How to use the square footage calculator
- Break the space into simple shapes. An L-shaped room is two rectangles; a bay window is a trapezoid; a round patio is a circle.
- Add one area per shape and enter its dimensions. Each area can use its own units.
- Subtract cut-outs such as a kitchen island, a fireplace hearth or a flower bed inside a lawn by ticking Subtract this area.
- Read the total in square feet, square yards, square meters and acres, and add a price per square foot or yard to estimate cost.
Area formulas
Measure in feet and inches? Convert the inches to a decimal first — 10 ft 6 in is 10.5 ft — or choose inches as the unit and enter 126.
Worked example: an L-shaped living room
- Split it into a 14 × 12 ft rectangle (168 sq ft) and an 8 × 6 ft rectangle (48 sq ft)
- Subtract a 3 × 5 ft hearth (15 sq ft)
- Total: 168 + 48 − 15 = 201 sq ft, or 22.3 sq yd
Unit conversions
| From | To | Multiply by |
|---|---|---|
| Square feet | Square yards | ÷ 9 |
| Square feet | Square meters | × 0.0929 |
| Square meters | Square feet | × 10.764 |
| Square feet | Acres | ÷ 43,560 |
| Square inches | Square feet | ÷ 144 |
Measuring tips
- Measure wall to wall at floor level for flooring, and add closets separately. For carpet and vinyl sold on rolls, also note the direction the material will run.
- For yards and lots, a long tape or a measuring wheel is faster than a tape measure; online maps with a measuring tool are handy for a first estimate.
- Irregular curves can be approximated with a few trapezoids: measure widths at regular intervals along the length and average them.
- Add waste after measuring, not by rounding every dimension up — the material calculators on this site do it for you.
Frequently asked questions
How do I calculate square footage of a room?
Multiply the length by the width in feet. A 12 × 15 ft room is 180 sq ft. For odd shapes, split the room into rectangles and add them up.
How many square feet are in an acre?
43,560 square feet. A square acre is about 208.7 feet on each side.
How many square feet in a square yard?
9 — a square yard is 3 ft × 3 ft.
Does square footage include walls?
For flooring and lawns you measure the surface you're covering. Real estate listings follow different rules (and usually measure exterior dimensions), so their numbers aren't directly comparable.