Hectares to Acres
Convert hectares to acres. The hectare is exact, the acre is not, and the result is marked as rounded rather than presented as exact.
ac = ha × 10000 ÷ 4046.873
NIST SP 811 (2008), Appendix B.8 — acre (based on U.S. survey foot) to square meter (m2) = 4.046 873 E+03
The hectare is the unit European agriculture and land registries run on, and the acre is what a lot of the English-speaking world still quotes, so anyone comparing land across a border ends up doing this sum. Only one of the two is a definition: a hectare is exactly ten thousand square metres, a square a hundred metres on a side. The acre is a survey unit whose published value is rounded, so a conversion out of hectares into acres cannot be exact no matter how it is written.
How it is calculated
ac = ha × 10000 ÷ 4046.873
The acre goes to square metres first, then to hectares. The 4046.873 is the value for the acre based on the U.S. survey foot, and NIST prints it rounded — so the result is accurate to seven figures rather than exact, and the tool marks it that way.
Common values
| hectares | acres |
|---|---|
| 0.5 | 1.2355218 |
| 1 | 2.4710437 |
| 2 | 4.9420874 |
| 5 | 12.355218 |
| 10 | 24.710437 |
| 20 | 49.420874 |
| 50 | 123.55218 |
| 100 | 247.10437 |
| 200 | 494.20874 |
| 500 | 1,235.5218 |
| 1,000 | 2,471.0437 |
Questions people ask
- How many acres is a hectare?
- About 2.471. A football pitch is close to three quarters of a hectare, which makes a hectare a little under one and a half pitches — a more useful picture than the number for most people.
- Why is the answer marked as rounded?
- Because the acre is. NIST publishes 4046.873 square metres for the survey acre, printed to seven figures rather than as an exact definition, so anything derived from it inherits that limit.
- Which acre does this use?
- The one based on the U.S. survey foot, which is what the published figure describes. The international acre differs by roughly four parts in a million, which matters only on very large holdings.
- How big is a hectare in square feet?
- A little over 107,639 square feet. If that number looks familiar it is because it is the square metre to square foot factor with four zeros after it.
Related tools
Acres to Hectares
Convert acres to hectares. A hectare is exactly 10,000 square metres; the acre is not exact, and this page says which acre it uses.
Square Meters to Square Feet
Convert square meters to square feet by dividing by the exact factor, not by multiplying by a rounded 10.76. Runs entirely in your browser.
Kilometers to Miles
Convert kilometers to miles instantly in your browser. One mile is exactly 1.609344 kilometers, the factor fixed by the international yard and pound agreement.
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