Acres to Hectares
Type acres (ac), see hectares (ha).
By Akash Yadav Updated 27 September 2026
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The formula
How to convert acres to hectares
To change acres into hectares, multiply by 0.40468564224.
hectares = acres × 0.40468564224
Going the other way: acres = hectares × 2.471053814672
1 acre = 0.40468564224 hectares. This factor is the exact definition of the unit, not a rounded estimate.
Worked example
You have 40 acres. Multiply by 0.40468564224. 40 × 0.40468564224 = 16.1874 ha.
Common values
Acres to hectares conversion table
| Acres (ac) | Hectares (ha) |
|---|---|
| 0.25 ac | 0.1012 ha |
| 0.5 ac | 0.2023 ha |
| 1 ac | 0.4047 ha |
| 2 ac | 0.8094 ha |
| 2.5 ac | 1.0117 ha |
| 5 ac | 2.0234 ha |
| 10 ac | 4.0469 ha |
| 20 ac | 8.0937 ha |
| 40 ac | 16.1874 ha |
| 50 ac | 20.2343 ha |
| 80 ac | 32.3749 ha |
| 100 ac | 40.4686 ha |
| 160 ac | 64.7497 ha |
| 640 ac | 258.9988 ha |
| 1000 ac | 404.6856 ha |
Before you rely on it
An exact factor, because the acre is defined in feet
An acre is 43,560 square feet and the foot is exactly 0.3048 m, so an acre is exactly 4046.8564224 m², or 0.40468564224 hectares. That factor terminates, so answers on this page are exact up to the decimals shown.
For a quick estimate, take 40 percent: 100 acres is roughly 40 hectares, against a true 40.47. Good enough for comparing farm listings, not for a deed.
The US Public Land Survey divides land into sections of 640 acres — one square mile — and quarter sections of 160 acres. A section is about 259 hectares.
Older US land records may use the US survey acre, about 4 parts per million larger than the international acre this page uses. On a 1000-acre property that is less than 0.002 hectares.
Common questions
Frequently asked questions
How many hectares is 1 acre?
1 acre is exactly 0.40468564224 hectares — about 0.405 ha.
How many hectares is 10 acres?
10 acres is about 4.047 hectares.
How many hectares is 100 acres?
100 acres is about 40.469 hectares.
How many hectares is 5 acres?
5 acres is about 2.023 hectares.
How many hectares is a square mile?
A square mile is exactly 640 acres, about 259 hectares.
Which is bigger, an acre or a hectare?
A hectare. 1 acre is only about 0.405 hectares, a little over 40 percent of one.
Keep going
Related converters
- Hectares to Acres ha → ac
- Acres to Square Feet ac → ft²
- Square Feet to Acres ft² → ac
- All area converters
Every factor on this page is listed in our conversion methodology.