Unit converter
Acres to Hectares Converter
An acre equals exactly 0.40468564224 hectares, since an acre is 4,046.8564224 square metres and a hectare is precisely 10,000 square metres. Feed an acreage into this tool and it returns the metric equivalent in hectares, with a quick table for the figures looked up most. It earns its keep on farms filing EU or metric subsidy forms, in surveying where imperial deeds meet metric mapping, and whenever an acre-based listing needs restating in hectares for an overseas buyer.
1 acre = 0.404686 hectares
Common acres to hectares values
| Acres | Hectares |
|---|---|
| 1 ac | 0.404686 ha |
| 2 ac | 0.809371 ha |
| 5 ac | 2.0234 ha |
| 10 ac | 4.0469 ha |
| 20 ac | 8.0937 ha |
| 50 ac | 20.2343 ha |
| 100 ac | 40.4686 ha |
How to convert
- Start from the area in acres.
- Multiply by 0.40468564224, because one acre is 4,046.8564224 square metres and a hectare is 10,000.
- The answer is that area in hectares.
- To reverse it, divide hectares by 0.40468564224, or multiply by about 2.471053815, to get acres.
- As a mental shortcut, take roughly two-fifths of the acreage: 10 acres is about 4 hectares.
hectares = acres × 0.40468564224
An acre measures 4,046.8564224 square metres and a hectare is 10,000 square metres, so dividing one by the other gives 0.40468564224. Multiplying acres by that exact constant yields hectares; dividing reverses the step.
- ac
- the area in acres you begin with
- 0.40468564224
- hectares in one acre (4,046.8564224 ÷ 10,000)
Worked example
A 4-acre field is 4 times 0.40468564224, which is about 1.6187 hectares. A 25-acre holding works out at close to 10.12 hectares.
Key facts
- One acre is exactly 0.40468564224 hectares.
- It takes about 2.471 acres to make one hectare.
- 100 acres equals roughly 40.47 hectares.
- A square mile (640 acres) is about 258.999 hectares.
Tips
- For a rough conversion, multiply acres by 0.4; the small remainder rounds it up slightly.
- When totalling several acreages, sum them first, then convert the total once.
Frequently asked questions
How many hectares are in 1 acre?+
Exactly 0.40468564224 hectares, since the acre is defined as 4,046.8564224 square metres against the hectare's 10,000.
Is an acre smaller than a hectare?+
Yes. An acre is roughly 0.405 of a hectare, so it takes about two and a half acres to fill one hectare.
How do I convert 100 acres?+
Multiply 100 by 0.40468564224 to get about 40.47 hectares.
Why so many decimal places?+
The acre comes from imperial yards, so its exact metric size is a long but fixed decimal rather than a round number.
Things to watch
- Old US-survey-foot acres differ from the international acre by a few parts per million, which only shows on very large estates.
Sources
Last updated: 2026-01-01
Conversions use internationally defined factors. Provided for general use; verify critical measurements independently.