Area Converter
Enter a number, pick the unit it's in, and every other area unit comes back at once: square inches, square feet, square yards, acres, square miles, and the metric set from square millimeters up to square kilometers. It's the one-stop version of the individual converters on this site, and the conversion chart below covers the same ground if you'd rather read a table.
How area unit conversion works
Every area conversion is a length conversion, squared. That one idea explains every number on this page.
A foot is 12 inches, so a square foot is 12 x 12 = 144 square inches. A yard is 3 feet, so a square yard is 3 x 3 = 9 square feet. A meter is 100 centimeters, so a square meter is 100 x 100 = 10,000 square centimeters. The squaring is why area factors grow so much faster than length factors, and forgetting it is the most common conversion mistake there is.
The bridge between the two systems is the foot. Since 1959 it has been defined as exactly 0.3048 meters, so a square foot is exactly 0.09290304 square meters, and NIST's conversion tables list the square inch at exactly 0.00064516 square meters for the same reason. Every US customary area unit converts to metric exactly through that one definition.
Area conversion chart
Read across from the unit you have to the one you want. Multiply by the number in the table.
| From | To | Multiply by |
|---|---|---|
| Square inches | Square feet | 0.006944 (divide by 144) |
| Square inches | Square centimeters | 6.4516 |
| Square feet | Square inches | 144 |
| Square feet | Square yards | 0.1111 (divide by 9) |
| Square feet | Square meters | 0.092903 |
| Square feet | Acres | 0.00002296 (divide by 43,560) |
| Square yards | Square feet | 9 |
| Square yards | Square meters | 0.836127 |
| Acres | Square feet | 43,560 |
| Acres | Square meters | 4,046.86 |
| Acres | Hectares | 0.404686 |
| Square miles | Acres | 640 |
| Square miles | Square kilometers | 2.589988 |
| Square meters | Square feet | 10.763910 |
| Square meters | Square centimeters | 10,000 |
| Hectares | Acres | 2.471054 |
| Hectares | Square feet | 107,639.1 |
| Square kilometers | Hectares | 100 |
| Square kilometers | Square miles | 0.386102 |
US customary area units
| Unit | Equal to | In square meters |
|---|---|---|
| 1 square inch | 1/144 square foot | 0.00064516 m2 (exact) |
| 1 square foot | 144 square inches | 0.09290304 m2 (exact) |
| 1 square yard | 9 square feet | 0.83612736 m2 (exact) |
| 1 acre | 43,560 square feet | 4,046.856 m2 |
| 1 square mile | 640 acres | 2,589,988 m2 |
The acre is a leftover from farming rather than geometry: historically the land a team of oxen could plow in a day, standardized as a strip one furlong long and one chain wide. That's why it lands on an odd 43,560 square feet. A square acre would be about 208.7 feet on each side.
One detail for anyone working with older land records. The acre used to be defined through the US survey foot, which differed from the international foot by about two parts per million. NIST retired it, and from January 1, 2023 the survey foot should be avoided except for historic and legacy applications, with the acre now based on the international foot. The difference is about 0.017 square meters per acre, which matters to a surveyor and to nobody else.
Metric area units
Metric area units step up by a factor of 100 each time, because each length step is a factor of 10. NIST lays out the ladder from square centimeters up to hectares:
| Unit | Equal to | In square meters |
|---|---|---|
| 1 square millimeter | 1/100 square centimeter | 0.000001 m2 |
| 1 square centimeter | 100 square millimeters | 0.0001 m2 |
| 1 square meter | 10,000 square centimeters | 1 m2 |
| 1 are | 100 square meters | 100 m2 |
| 1 hectare | 100 ares | 10,000 m2 |
| 1 square kilometer | 100 hectares | 1,000,000 m2 |
The hectare is a square 100 meters on each side and is the metric world's standard land unit, playing the role the acre plays in the US. One hectare is just under two and a half acres.
Which unit for which job
Square inches and square centimeters for small surfaces: tiles, screens, fabric, packaging.
Square feet and square meters for rooms, homes, and commercial floor space. The square footage calculator and the square meter calculator both start from length times width.
Square yards mostly for carpet and some landscaping materials.
Acres and hectares for lots, farms, and land parcels.
Square miles and square kilometers for cities, counties, and countries.
Single-direction converters
For one conversion at a time, with worked examples and a reference table for that pair:
- Square feet to square meters
- Square meters to square feet
- Square footage to acres
- Square inches to square feet
- Square feet to linear feet, for boards and trim
- Square feet to cubic yards, for concrete, mulch, and gravel
The last two aren't pure area conversions. Linear feet need a board width, and cubic yards need a depth, which is why they have their own tools.
Common mistakes
Using the length factor for area. A meter is 3.28 feet, but a square meter is 10.76 square feet. Always square the length factor.
Dividing square centimeters by 100 to get square meters. It's 10,000.
Treating a square yard as 3 square feet. It's 9.
Converting area into length. Square feet can't become feet, and square meters can't become meters. They measure different things.
Rounding the factor too hard. 0.093 instead of 0.092903 adds about 0.1 percent. That's fine for a listing and noticeable on a commercial lease.
Frequently asked questions
How do you convert area units?
Square the length conversion factor. A foot is 0.3048 meters, so a square foot is 0.3048 x 0.3048 = 0.092903 square meters. The same rule gives 144 square inches in a square foot and 9 square feet in a square yard.
How many square feet are in an acre?
43,560 square feet. An acre is also 4,046.86 square meters, or about 0.405 hectares.
How many acres are in a hectare?
2.471 acres. A hectare is 10,000 square meters, a square 100 meters on each side.
How many square feet are in a square meter?
10.7639 square feet. Going the other way, one square foot is 0.092903 square meters.
How many square kilometers are in a square mile?
2.59 square kilometers. A square mile is also 640 acres, and a square kilometer is 100 hectares or about 0.386 square miles.
How many square centimeters are in a square inch?
6.4516, exactly. That follows from an inch being exactly 2.54 centimeters, and 2.54 squared is 6.4516.
What is the SI unit of area?
The square meter (m2). Every other metric area unit is a power of 100 above or below it, and every US customary unit is defined as an exact multiple of it through the international foot.
Sources
- NIST Guide to the SI, Appendix B.9 conversion factors
- SI units: area, NIST Office of Weights and Measures
- U.S. survey foot, NIST
Related tools
Square feet to square meters | Square meter calculator | Square footage to acres | Square footage chart