acres to hectares formula
To convert acres to hectares, multiply the number of acres by 0.40468564224. In symbols: ha = ac × 0.40468564224.
One acre equals 0.40468564224 hectares, and one hectare equals 2.47105381467 acres. The international acre is exactly 4,046.8564224 square meters, so one acre is 0.40468564224 hectares. The US survey acre differs by two parts per million.
Worked example
Suppose you have 5 acres and need the answer in hectares.
- Write the formula: ha = ac × 0.40468564224.
- Put in the number: 5 × 0.40468564224 = 2.023428211.
- Round to suit the job. 2.023 ha is accurate enough for most everyday uses.
So 5 ac is 2.023428211 ha. To check, convert back: 2.023428211 ha is 5 ac.
Common acres to hectares values
| acres (ac) | hectares (ha) |
|---|---|
| 1 | 0.4046856422 |
| 2 | 0.8093712845 |
| 5 | 2.023428211 |
| 10 | 4.046856422 |
| 20 | 8.093712845 |
| 50 | 20.23428211 |
| 100 | 40.46856422 |
Reference points
Some familiar amounts in acres, converted to hectares:
- 1 ac, about a football pitch: 0.404686 ha
- 5 ac, a small farm plot: 2.02343 ha
- 40 ac, a quarter-quarter section: 16.1874 ha
- 640 ac, one square mile: 258.999 ha
Where you will use it
Farmland, parks and building plots are sold in acres in the US, UK and India, while maps, government records and international reports use hectares. Land deals across borders need both.
Quick mental math
Multiply by 0.4. Five acres is about 2 ha, and the exact value is 2.02 ha. Rule of thumb: multiply by 0.4. For 5 ac this gives 2 ha against the exact 2.023, an error of 1.2 percent.
Going the other way
Need the reverse? Use the hectares to acres converter. For comparison, 1 ha is 2.4710538 ac. To compare every area unit at once, open the area converter.
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