Unit & Measurement Tables
Area Conversion Table
Area is the unit people get wrong most often, because the conversion factor is the square of the length factor and almost nobody squares it. A metre is 3.28084 ft, so it is tempting to say a square metre is about 3.28 ft². It is 10.76 ft², because both the width and the height stretch by the same factor. That single mistake turns a 100 m² flat into a 328 ft² flat instead of a 1,076 ft² one — a factor of three.
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The second complication is that land area uses units with no metric equivalent at all. The acre is a relic of the strip-farming system: a chain (66 ft) wide by a furlong (660 ft) long, which multiplies to exactly 43,560 ft². The hectare was invented as its metric replacement and is exactly 10,000 m², so the two are close but never equal — one hectare is 2.4711 acres, and land agents quote both depending on the country.
The tables below are computed from the 1959 yard definition (0.9144 m exactly), which makes every foot-based figure exact rather than rounded. Rows run from a single square metre to a thousand acres, covering floor plans, gardens, building plots and farmland.
Square metres to square feet, square yards, acres and hectares
| Square metres | Square feet | Square yards | Acres | Hectares |
|---|---|---|---|---|
| 1 | 10.76 | 1.2 | 0.000247 | 0.0001 |
| 5 | 53.82 | 5.98 | 0.001236 | 0.0005 |
| 10 | 107.64 | 11.96 | 0.002471 | 0.001 |
| 25 | 269.1 | 29.9 | 0.006178 | 0.0025 |
| 50 | 538.2 | 59.8 | 0.012355 | 0.005 |
| 100 | 1,076.39 | 119.6 | 0.024711 | 0.01 |
| 250 | 2,690.98 | 299 | 0.061776 | 0.025 |
| 500 | 5,381.96 | 598 | 0.123553 | 0.05 |
| 1,000 | 10,763.91 | 1,195.99 | 0.247105 | 0.1 |
| 2,500 | 26,909.78 | 2,989.98 | 0.617763 | 0.25 |
| 5,000 | 53,819.55 | 5,979.95 | 1.235527 | 0.5 |
| 10,000 | 107,639.1 | 11,959.9 | 2.471054 | 1 |
One square metre is 10.7639 ft². The 100 m² row is roughly the footprint of a two-bedroom flat in most of Europe.
Square feet to square metres, square yards and acres
| Square feet | Square metres | Square yards | Acres |
|---|---|---|---|
| 100 | 9.29 | 11.11 | 0.0023 |
| 250 | 23.23 | 27.78 | 0.0057 |
| 500 | 46.45 | 55.56 | 0.0115 |
| 750 | 69.68 | 83.33 | 0.0172 |
| 1,000 | 92.9 | 111.11 | 0.023 |
| 1,500 | 139.35 | 166.67 | 0.0344 |
| 2,000 | 185.81 | 222.22 | 0.0459 |
| 2,500 | 232.26 | 277.78 | 0.0574 |
| 3,000 | 278.71 | 333.33 | 0.0689 |
| 4,000 | 371.61 | 444.44 | 0.0918 |
| 5,000 | 464.52 | 555.56 | 0.1148 |
| 10,000 | 929.03 | 1,111.11 | 0.2296 |
Nine square feet make one square yard exactly, because a yard is three feet in both directions. 43,560 ft² is one acre, a figure that comes from the old chain measure of 66 × 660 ft.
Acres to square metres, square feet, hectares and square miles
| Acres | Square metres | Square feet | Hectares | Square miles |
|---|---|---|---|---|
| 0.1 | 405 | 4,356 | 0.0405 | 0.0002 |
| 0.25 | 1,012 | 10,890 | 0.1012 | 0.0004 |
| 0.5 | 2,023 | 21,780 | 0.2023 | 0.0008 |
| 1 | 4,047 | 43,560 | 0.4047 | 0.0016 |
| 2 | 8,094 | 87,120 | 0.8094 | 0.0031 |
| 5 | 20,234 | 217,800 | 2.0234 | 0.0078 |
| 10 | 40,469 | 435,600 | 4.0469 | 0.0156 |
| 20 | 80,937 | 871,200 | 8.0937 | 0.0313 |
| 50 | 202,343 | 2,178,000 | 20.2343 | 0.0781 |
| 100 | 404,686 | 4,356,000 | 40.4686 | 0.1563 |
| 500 | 2,023,428 | 21,780,000 | 202.3428 | 0.7813 |
| 1,000 | 4,046,856 | 43,560,000 | 404.6856 | 1.5625 |
640 acres make one square mile, so a quarter section of land is 160 acres. One acre is 0.4047 ha, which is why a 40 acre field is just over 16 ha.
Hectares to acres, square metres and square feet
| Hectares | Acres | Square metres | Square feet |
|---|---|---|---|
| 0.1 | 0.2471 | 1,000 | 10,764 |
| 0.25 | 0.6178 | 2,500 | 26,910 |
| 0.5 | 1.2355 | 5,000 | 53,820 |
| 1 | 2.4711 | 10,000 | 107,639 |
| 2 | 4.9421 | 20,000 | 215,278 |
| 5 | 12.3553 | 50,000 | 538,196 |
| 10 | 24.7105 | 100,000 | 1,076,391 |
| 20 | 49.4211 | 200,000 | 2,152,782 |
| 50 | 123.5527 | 500,000 | 5,381,955 |
| 100 | 247.1054 | 1,000,000 | 10,763,910 |
| 500 | 1,235.5269 | 5,000,000 | 53,819,552 |
| 1,000 | 2,471.0538 | 10,000,000 | 107,639,104 |
One hectare is 2.4711 acres. A hectare is a square 100 m on a side, which is why it is the standard unit for farmland outside the US.
How to Use These Tables
- Floor plans: multiply square feet by 0.092903 to get square metres. A 1,200 ft² apartment is 111.48 m².
- Land listings: multiply acres by 0.404686 to get hectares, or hectares by 2.47105 to get acres. A 40 acre field is 16.19 ha.
- Square the linear factor, never use it directly: 1 m = 3.28084 ft, but 1 m² = 10.7639 ft². If you convert a length and then a width separately and multiply, you get the right answer; if you convert the area with the length factor you are out by a factor of 3.28.
- Roofing and flooring: order material in the unit the supplier sells. Shingles come by the square (100 ft²), tiles by the square metre, so convert the measured area into the ordering unit before adding the waste allowance.
Common Questions
Why is one square metre not 3.28 square feet?
Because area scales with the square of length. One metre is 3.28084 ft, so one square metre is 3.28084² = 10.7639 ft². The same trap applies to cubic measures, where the factor is cubed.
How many square feet are in an acre?
Exactly 43,560. An acre is one chain by one furlong, which is 66 ft × 660 ft. That definition predates the metric system and is still the legal definition in the US and UK.
Is a hectare bigger than an acre?
Yes, about 2.47 times bigger. A hectare is 10,000 m² and an acre is 4,046.86 m². Roughly, a hectare is two and a half acres.
How do I convert square feet to square yards?
Divide by 9. A yard is exactly three feet, so a square yard is 3 × 3 = 9 ft². Carpet in the US is priced by the square yard for this reason.
What is a square in roofing?
One hundred square feet of roof surface, a US roofing trade unit. A 2,000 ft² roof is 20 squares. It is a measure of area, not of the number of shingle bundles, which depends on the product.
Does the table use US or imperial acres?
There is only one acre. The US and imperial systems diverge on gallons and tons, but the acre, foot, yard and mile were unified by the 1959 agreement and are identical in both.
More Unit & Measurement Tables
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units — National Institute of Standards and Technology
- Refinement of values for the yard and the pound (1959 agreement) — National Bureau of Standards
- Weights and measures — acre, hectare and survey units — National Institute of Standards and Technology
Filed with Unit Conversion calculations.