How to convert square miles to hectares
ha = mi² × 258.998811Multiply the value in square miles by 258.998811. To go the other way, multiply by 0.003861021585 (or divide by 258.998811).
A square mile is larger than a hectare: one square mile contains 258.998811 hectares.
Worked examples
- 1 square mile1 mi² × 258.998811 = 258.998811 ha
- 5 square miles5 mi² × 258.998811 = 1,294.994055 ha
- 10 square miles10 mi² × 258.998811 = 2,589.98811 ha
- 20 square miles20 mi² × 258.998811 = 5,179.976221 ha
- 100 square miles100 mi² × 258.998811 = 25,899.8811 ha
Square miles to hectares conversion table
Values are calculated by the conversion engine and rounded to 8 significant figures.
| Square miles (mi²) | Hectares (ha) |
|---|---|
| 0.1 mi² | 25.899881 ha |
| 0.25 mi² | 64.749703 ha |
| 0.5 mi² | 129.49941 ha |
| 1 mi² | 258.99881 ha |
| 2 mi² | 517.99762 ha |
| 3 mi² | 776.99643 ha |
| 4 mi² | 1,035.9952 ha |
| 5 mi² | 1,294.9941 ha |
| 6 mi² | 1,553.9929 ha |
| 7 mi² | 1,812.9917 ha |
| 8 mi² | 2,071.9905 ha |
| 9 mi² | 2,330.9893 ha |
| 10 mi² | 2,589.9881 ha |
| Square miles (mi²) | Hectares (ha) |
|---|---|
| 12 mi² | 3,107.9857 ha |
| 15 mi² | 3,884.9822 ha |
| 20 mi² | 5,179.9762 ha |
| 25 mi² | 6,474.9703 ha |
| 30 mi² | 7,769.9643 ha |
| 40 mi² | 10,359.952 ha |
| 50 mi² | 12,949.941 ha |
| 75 mi² | 19,424.911 ha |
| 100 mi² | 25,899.881 ha |
| 250 mi² | 64,749.703 ha |
| 500 mi² | 129,499.41 ha |
| 1,000 mi² | 258,998.81 ha |
About the units
Square mile (mi²)
640 acres. Used for US counties, states and wildfire extents. One square mile equals 2,589,988.11 square meters (m²).
Hectare (ha)
Exactly 10,000 m² — a square 100 m on a side, about 2.47 acres. The standard unit for farmland and forestry worldwide.
Frequently asked questions
How many hectares are in one square mile?
There are 258.998811 hectares in one square mile, and this value is exact by definition.
How do I convert square miles to hectares?
Multiply the number of square miles by 258.998811. For example, 10 mi² × 258.998811 = 2,589.98811 ha.
How many square miles are in one hectare?
One hectare equals 0.003861021585 square miles. That is the reverse factor, 1 ÷ 258.998811.
What is 10 square miles in hectares?
10 mi² = 2,589.98811 ha.
Is this mi² to ha converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.