Acres to Hectares Converter
Type acres to get hectares. An acre is about four tenths of a hectare, so 10 acres is about 4 ha.
10 ac =
4.0469ha
10 acres is 4.0469 hectares.
- 1 ac
- 0.4047 ha
- 1 ha
- 2.4711 ac
How to convert acres to hectares
Multiply acres by 0.40468564224. An acre is 43,560 square feet, and with the foot fixed at 0.3048 m that is exactly 4,046.8564224 m². A hectare is 10,000 m², so one acre is 0.4047 ha.
A 25 acre field is 25 × 0.4047 = 10.12 hectares. A square mile, 640 acres, is 259 hectares, and a 2.5 acre plot comes to just over one hectare (1.0117 ha).
Older US land records may use the survey acre, based on the US survey foot. It is larger by only about 4 parts per million, roughly 16 m² on a 1,000 acre farm, and the survey foot was retired at the end of 2022.
hectares = acres × 0.40468564224
- One acre is 43,560 square feet; a square mile is 640 acres. Source: NIST Handbook 44, Appendix C: General Tables of Units of Measurement.
- The hectare (10,000 m²) is a non-SI unit accepted for use with the SI. Source: BIPM, The International System of Units (SI Brochure, 9th edition).
How to estimate acres to hectares in your head
Take two fifths. An acre is 0.405 of a hectare, so 0.4 is only 1.2% low: 25 acres × 0.4 = 10 ha, against the exact 10.12. For a closer figure, add 1% back on.
Another way is to remember that 5 acres is just over 2 hectares (2.02), and scale from there.
Acres to hectares chart
Land areas from a house lot to a square mile.
| Acres (ac) | Hectares (ha) | Example |
|---|---|---|
| 0.25 | 0.1012 | |
| 0.5 | 0.2023 | |
| 1 | 0.4047 | |
| 2 | 0.8094 | |
| 2.5 | 1.0117 | about one hectare |
| 5 | 2.0234 | |
| 10 | 4.0469 | |
| 15 | 6.0703 | |
| 20 | 8.0937 | |
| 25 | 10.1171 |
Show all 21 rowsShow fewer
| 40 | 16.1874 | |
| 50 | 20.2343 | |
| 80 | 32.3749 | |
| 100 | 40.4686 | |
| 160 | 64.7497 | a quarter of a square mile |
| 200 | 80.9371 | |
| 250 | 101.171 | |
| 320 | 129.499 | |
| 500 | 202.343 | |
| 640 | 258.999 | one square mile |
| 1,000 | 404.686 |
Frequently Asked Questions
How many hectares is 1 acre?
One acre is 0.4047 hectares, so about two fifths of a hectare. It takes about 2.47 acres to make one hectare.
How many hectares is 100 acres?
100 acres is 40.47 hectares, a little over 0.4 square kilometers.
Which is bigger, an acre or a hectare?
The hectare. It is 10,000 m², while an acre is 4,046.86 m², so a hectare is about two and a half acres.
How do I convert acres to square meters instead?
Multiply by 4,046.8564224. Two acres is 8,093.7 m², and 1,000 acres is 4.05 square kilometers. Dividing the square meters by 10,000 then gives hectares.