# Square Footage Calculator

> Add one row for each room or shape: rectangle, triangle or circle. Type sizes like 10 ft 6 in, and tick Subtract for a closet or a cutout. The calculator totals square feet and also shows square yards, square meters and acres. Two rooms minus a closet make 294 sq ft.

Canonical: https://receiptscanner.co/tools/square-footage-calculator
Updated: 2026-10-28 · Sources re-checked by: 2027-10-28

This is a free interactive calculator that runs in the browser. Nothing you type is stored or sent. Results are estimates.

## How it works

Rectangle: length × width. Triangle: base × height ÷ 2. Circle: π × (diameter ÷ 2)². Each row is multiplied by its quantity. Rows marked Subtract are taken off the total, which never goes below zero. Feet and inches are read as feet, so 10 ft 6 in is 10.5. Then square yards = square feet ÷ 9, square meters = square feet × 0.09290304, and acres = square feet ÷ 43,560.

**Square footage of common room sizes**

| Room | Square feet | Square meters |
| --- | --- | --- |
| 10 × 10 ft | 100 | 9.3 |
| 12 × 12 ft | 144 | 13.4 |
| 12 × 16 ft | 192 | 17.8 |
| 14 × 20 ft | 280 | 26 |
| 20 × 20 ft | 400 | 37.2 |

**Converting square feet**

| Square feet | Square yards | Square meters | Acres |
| --- | --- | --- | --- |
| 100 | 11.1 | 9.3 | 0.0023 |
| 500 | 55.6 | 46.5 | 0.0115 |
| 1,000 | 111.1 | 92.9 | 0.023 |
| 5,000 | 555.6 | 464.5 | 0.1148 |

## Worked example: two rooms minus a closet

1. Living room: 15 × 12 = 180 sq ft.
2. Kitchen: 10 ft 6 in is 10.5 ft, so 10.5 × 12 = 126 sq ft.
3. Closet taken off: 4 × 3 = 12 sq ft.
4. Total: 180 + 126 − 12 = 294 square feet.
5. That is 32.67 square yards, 27.31 square meters and 0.0067 acres.

## FAQ

### How do I calculate square footage?
Multiply length by width in feet. For several rooms, work out each one and add them. For an L shape, split it into two rectangles and add them.

### How do I measure a room with inches?
Type the feet and inches together, for example 10 ft 6 in or 10'6", and the calculator turns it into 10.5 feet. You can also type 10.5 or 10 1/2.

### How do I find the area of a triangle or a circle?
A triangle is half of base times height. A circle is π times the radius squared, which is the diameter halved. Pick the shape in the row and type the measurements.

### How do I leave out a closet, a stairwell or a pool?
Add it as its own row and tick Subtract. Its area comes off the total, so the answer only counts the space you want.

### How many square feet are in an acre?
43,560. A lot of 100 ft by 435.6 ft is one acre. Square yards and square meters are shown for the same total.

### Is square footage of a house measured inside or outside?
It depends on who is counting. Flooring and paint need the inside, finished area. Listings and appraisals follow their own rules, so measure the way the job needs.

## Sources

- [Square foot: 1 ft² = 0.09290304 m² exactly (from 1 ft = 0.3048 m)](https://en.wikipedia.org/wiki/Square_foot) (checked 2026-10-28)
- [International yard and pound agreement (1959): 1 yard = 0.9144 m](https://en.wikipedia.org/wiki/International_yard_and_pound) (checked 2026-10-28)

This calculator is an estimate for planning. Real rooms are rarely exact rectangles, so measure carefully and add a little extra when you buy materials.