Acres to Hectares
An instant acres-to-hectares converter, with the formula and a reference table below.
| Acres | Hectares |
|---|---|
| 1 ac | 0.404686 ha |
| 2 ac | 0.809371 ha |
| 3 ac | 1.214057 ha |
| 5 ac | 2.023428 ha |
| 10 ac | 4.046856 ha |
| 25 ac | 10.117141 ha |
| 50 ac | 20.234282 ha |
| 100 ac | 40.468564 ha |
How to use
- Enter a value in the Acres field.
- The Hectares figure appears immediately — no button to press.
- Typing in the Hectares field converts back to Acres the same way.
- Use the reference table for the values that come up most often.
Acres to Hectares formula
The factor from acres to hectares is 0.404685642.
ha = ac × 0.404685642
Why this factor: the acre and the hectare are both defined against the square meter, so dividing one definition by the other gives 0.404685642 directly. Both definitions are set out in full below.
To go the other way, divide by 0.404685642 — or use the Hectares to Acres converter, which is the same calculation reversed.
Worked example
Take 250 ac and multiply by the factor 0.404685642: the result is 101.171411 ha.
250 ac × 0.404685642 = 101.171411 ha
The converter above does this for any value you type, in either direction.
What is an acre?
An acre is the customary land area unit of the US and UK, historically a day's ploughing for one team of oxen.
Definition: One chain by one furlong — 43,560 square feet — which is exactly 4,046.8564224 square meters.
Where it is used: US and UK property and farmland, development parcels, and land sales.
Worth knowing: 640 acres make one square mile, the basis of the US Public Land Survey grid.
What is a hectare?
A hectare is the standard metric unit of land area — a 100-meter square.
Definition: Exactly 10,000 square meters, which is one square hectometer.
Where it is used: Agricultural and forestry land, development sites, and land-use statistics worldwide.
Worth knowing: Roughly two and a half acres, and almost exactly the area of an international rugby pitch.
Acres vs Hectares
The acre is an imperial unit while the hectare is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many hectares are in an acre?
One acre equals 0.404685642 hectares.
What is the formula to convert acres to hectares?
Multiply the number of acres by 0.404685642. To reverse it, divide by 0.404685642 instead.
How do I convert hectares back to acres?
Divide by 0.404685642, which is the same as multiplying by 2.47105381.
How many hectares are in 10 acres?
10 ac works out to 4.046856 ha.
Is there anything to watch out for with acres?
640 acres make one square mile, the basis of the US Public Land Survey grid.
How is the acre defined?
One chain by one furlong — 43,560 square feet — which is exactly 4,046.8564224 square meters.