How to convert area units
Choose the unit you have in From and the unit you want in To, enter the area and press Convert. The converter works with an area you already know; if you only have the dimensions of a space, multiply them first. Negative areas are rejected.
How the conversion works
Every unit is stored as a number of square meters, and each factor is the square of a length factor. Because the foot is exactly 0.3048 m, a square foot is exactly 0.3048 × 0.3048 = 0.09290304 m². In the same way a square inch is exactly 6.4516 cm². The acre is defined as 43,560 square feet, which makes it exactly 4,046.8564224 m², and a square mile is 640 acres.
The metric land units are simple powers of ten: an are is 100 m² (10 m × 10 m), a hectare is 100 ares or 10,000 m² (100 m × 100 m), and a square kilometer is 100 hectares.
| Area | Equals |
|---|---|
| 1 square inch | 6.4516 cm² |
| 1 square foot | 0.09290304 m² |
| 1 square yard | 0.83612736 m² |
| 1 acre | 4046.8564224 m² |
| 1 square mile | 2.589988110336 km² |
| 1 square meter | ≈ 10.76391 ft² |
| 1 hectare | ≈ 2.471054 ac |
| 1 square kilometer | ≈ 0.386102 mi² |
Worked examples
- A 12 ft × 15 ft room in square meters: 12 × 15 = 180 ft², and 180 × 0.09290304 ≈ 16.72 m². Converting the sides first (3.6576 m × 4.572 m) gives the same result.
- An 85 m² apartment in square feet: 85 ÷ 0.09290304 ≈ 914.93 ft².
- 5 hectares in acres: 50,000 m² ÷ 4,046.8564224 ≈ 12.355 ac.
- Wire cross-section: a round conductor 0.1 in (100 mil) across has an area of 100² = 10,000 circular mils, which converts to about 5.067 mm².
Working out an area before converting
Measure every side in the same unit, then use the formula for the shape. A rectangle is length × width, a triangle is base × height ÷ 2 and a circle is π × radius². An L-shaped room can be split into two rectangles and the results added. For example, a round patio 12 ft across has a radius of 6 ft, so its area is π × 6² ≈ 113.1 ft², which converts to about 10.51 m². Enter the area, not the side lengths, in the converter.
Square meters to square feet
| m² | ft² |
|---|---|
| 1 | 10.76 |
| 5 | 53.82 |
| 10 | 107.64 |
| 20 | 215.28 |
| 50 | 538.2 |
| 100 | 1076.39 |
| 200 | 2152.78 |
| 1000 | 10763.91 |
Acres and hectares
| ac | ha | m² |
|---|---|---|
| 0.25 | 0.101 | 1011.714 |
| 0.5 | 0.202 | 2023.428 |
| 1 | 0.405 | 4046.856 |
| 5 | 2.023 | 20234.282 |
| 10 | 4.047 | 40468.564 |
| 640 | 258.999 | 2589988.11 |
| ha | ac |
|---|---|
| 0.5 | 1.236 |
| 1 | 2.471 |
| 5 | 12.355 |
| 10 | 24.711 |
| 100 | 247.105 |
Units that are easy to confuse
- Acre and hectare. Both are used for land, but a hectare is about 2.471 acres, and an acre about 0.4047 hectares. Treating them as roughly equal more than doubles or halves a plot.
- Acre shape. An acre has no fixed shape. It was traditionally one chain by one furlong (66 ft × 660 ft); as a square it would be about 208.71 ft, or 63.61 m, on each side.
- Survey acre. US land records based on the US survey foot use an acre about 4 parts per million larger, roughly 0.016 m² more per acre. This converter uses the international foot, so the difference only matters for precise work over very large areas.
- Circular mil and square mil. A circular mil is the area of a circle one mil (a thousandth of an inch) in diameter, so it is π/4 of a square mil. It is used for wire and cable sizes in North America because a round wire's area in circular mils is simply its diameter in mils squared.
- "10 feet square" and "10 square feet". The first describes a square 10 ft on each side, which is 100 ft². The second is an area of 10 ft², such as a 2 ft × 5 ft rug.
Common mistakes
- Using the length factor. One meter is about 3.28 ft, but one square meter is about 10.76 ft². If the sides of a shape double, its area grows four times.
- Rounding before squaring. Squaring 3.28 turns 1,000 m² into 10,758.4 ft² instead of about 10,763.91 ft². Use the full factor, as the converter does.
- Multiplying mixed units. Convert all sides to the same unit before multiplying. Feet times meters is neither square feet nor square meters. The length converter handles the sides.
Frequently asked questions
How many square feet are in an acre?
Exactly 43,560 square feet, which is also 4,840 square yards.
How big is a hectare?
A square 100 m on each side, or 10,000 m². That is about 2.471 acres. One hundred hectares make one square kilometer.
How many acres are in a square mile?
640. A square mile is also exactly 2.589988110336 km², so a square kilometer is about 0.3861 square miles.
How large is an American football field?
Including the end zones, the field is 360 ft × 160 ft, or 57,600 ft². That is about 1.32 acres, or about 5,351 m².
Supported units
- Square kilometer (km²)
- Hectare (ha)
- Are (a)
- Square meter (m²)
- Square decimeter (dm²)
- Square centimeter (cm²)
- Square millimeter (mm²)
- Square mile (mi²)
- Acre (ac)
- Square yard (yd²)
- Square foot (ft²)
- Square inch (in²)
- Circular mil (cmil)