How to use the area converter
Enter an area in the Value box, select the unit you start from and the unit you want, then press Convert. The swap button flips the two units. Below the result a table shows the same area in all ten supported units, from square millimeters up to square miles.
This is handy for comparing floor plans, flat and house listings, garden and land plots, or farm sizes given in different systems.
How the conversion works
Area units are squares of length units, so each factor is the length factor multiplied by itself:
- 1 inch = 2.54 cm, so 1 in² = 6.4516 cm²
- 1 ft² = 144 in² = 0.09290304 m²
- 1 yd² = 9 ft²
- 1 acre = 43,560 ft² = 4,046.8564224 m²
- 1 square mile = 640 acres = 2.589988110336 km²
- 1 hectare = 10,000 m², and 1 km² = 100 hectares
Result = Value × (base units per source unit) / (base units per target unit). All of these definitions are exact, so only the final display is rounded.
Worked example
A 50 m² apartment in square feet: 50 / 0.09290304 = 538.195521 ft² (six decimals). The reverse also works: 538.195521 × 0.09290304 is 50 m².
Good to know
- A common mistake is to use the length factor for areas. One meter is about 3.28 feet, but one square meter is about 10.76 square feet, because both sides are converted.
- An acre is about 40% of a hectare: 1 ha is about 2.471 acres.
- A square mile is exactly 640 acres, which is why US land surveys often divide a section into quarter sections of 160 acres.
- The acre used here is the international acre, based on the international foot. The older US survey acre differs by only about 4 parts per million.
- Results show up to six decimals; very small values appear in scientific notation. Negative areas are rejected.