Hectares to Square Miles
Convert hectares (ha) to square miles (mi²). Both measure surface measurement, and the conversion comes up in real estate, farming, construction work.
The Formula
``
square miles = hectares × 0.00386102158542
hectares = square miles × 258.998811034
`
One hectare is 0.003861 square miles, and one square mile is 258.9988 hectares.
Conversion Table
| Hectares | Square Miles |
|---|---|
| 1 ha | 0.003861 mi² |
| 2 ha | 0.007722 mi² |
| 5 ha | 0.019305 mi² |
| 10 ha | 0.03861 mi² |
| 25 ha | 0.096526 mi² |
| 50 ha | 0.193051 mi² |
| 100 ha | 0.386102 mi² |
| 500 ha | 1.9305 mi² |
| 1,000 ha | 3.861 mi² |
The Other Direction
| Square Miles | Hectares |
|---|---|
| 1 mi² | 258.9988 ha |
| 2 mi² | 517.9976 ha |
| 5 mi² | 1,294.99 ha |
| 10 mi² | 2,589.99 ha |
| 25 mi² | 6,474.97 ha |
| 50 mi² | 12,949.94 ha |
| 100 mi² | 25,899.88 ha |
| 500 mi² | 129,499.41 ha |
| 1,000 mi² | 258,998.81 ha |
What Each Unit Is
Hectares (ha) — exactly 10,000 square metres, or a square 100 m on each side. The metric land unit, introduced with the metric system for agriculture and forestry.
Square Miles (mi²) — 640 acres, or 2.589988 square kilometres. The unit of the US Public Land Survey System, which divided the west into square-mile sections.
A Sense of Scale
A hectare is about 2.47 acres- A rugby pitch is roughly 1 hectare
- A survey township is 36 square miles
- San Francisco is 47 square miles
Precision
The factor 0.00386102158542 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
In Code
`javascript
const hectareToSquareMile = (value) => value * 0.00386102158542;
``
Where This Conversion Comes Up
- Real estate
- Farming
- Construction
- Landscaping
- Flooring
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 ha with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 ha becomes | Error |
|---|---|---|---|
| 0 | 0 | 0 | 100.0000% |
| 1 | 0 | 0 | 100.0000% |
| 2 | 0 | 0 | 100.0000% |
| 3 | 0.004 | 0.548 | 3.5995% |
| 4 | 0.0039 | 0.5343 | 1.0095% |
The right number of significant figures is set by your input, not by the converter. If you measured hectares to three significant figures, the answer in square miles is only good to three — writing more digits claims precision the measurement never had.