Area Converter

How area units are built

An area unit is a square whose side is a length unit. A square meter is a square 1 m on each side; a square foot is a square 1 ft on each side. Because the foot is exactly 0.3048 m, a square foot is exactly 0.3048 × 0.3048 = 0.09290304 m². Every customary area in this converter is exact in the same way.

Land has its own units:

• Hectare: a square 100 m on each side, 10,000 m². It is not an SI unit but is accepted for use with the SI and is the standard land unit in most countries.
• Acre: 43,560 square feet, historically a strip one furlong (660 ft) long and one chain (66 ft) wide. With the international foot that is exactly 4,046.8564224 m², a little over 0.4 ha.
• Square mile: 640 acres, the size of a “section” in the US public land survey.

The conversion formula

Each unit has an exact size in square meters, and converting multiplies by the ratio of the two sizes:

value

the area you enter

size

one unit in square meters, e.g. 0.09290304 m² for a square foot and 10,000 m² for a hectare

An area factor is always the square of the matching length factor. There are 3.280839895 feet in a meter, so there are 3.280839895² = 10.76391042 square feet in a square meter, and 3 feet in a yard means 9 square feet in a square yard.

Worked examples

A 100 m² apartment in square feet. A square foot is 0.09290304 m², so divide: 100 ÷ 0.09290304 = 1,076.391042 ft².

A 12 ft by 15 ft room in square meters. Multiply the sides first: 12 × 15 = 180 ft². Then 180 × 0.09290304 = 16.7225472 m². Converting the sides to meters first (3.6576 m × 4.572 m) gives the same exact answer.

An acre in hectares. 4,046.8564224 m² ÷ 10,000 m² = 0.40468564224 ha; the other way, a hectare is 2.471053815 acres.

Common area conversions

Where area conversions go wrong

• Using the length factor. Multiplying square meters by 3.28 instead of 10.76 gives a floor area about 3.3 times too small. Area factors are squared: 1 m = 3.28 ft, but 1 m² = 10.76 ft².
• Square feet are not feet. A floor 10 ft on each side is 100 ft². A floor of 10 ft² is only about 3.16 ft on each side. The same goes for “10 meters squared”: it can be read as 10 m² or as a square 10 m on a side (100 m²), so write m² to be clear. Add a third dimension and you have a volume: see the volume converter.
• Convert sides or areas, not a mix. For a room, either multiply the sides in feet and convert the area, or convert each side with the length converter and multiply. Converting one side and not the other gives a meaningless number.
• The survey acre. Until the end of 2022 much US land was measured with the survey foot, which makes an acre 4,046.872609874 m², about 0.016 m² (4 parts per million) more than the international acre used here. NIST’s SP 811 conversion table still lists that survey-foot value. The difference is negligible for a single lot but can appear in large surveys.