Hectares to Square Miles Converter

About the ha to mi² calculation

One hectare is exactly 0.00386102 square miles, so converting between them is a single multiplication. Enter any value above and the result updates as you type. Exactly 10,000 m², the metric standard for farmland and land registry. Used for land and territory area in the US and UK. One square mile is exactly 640 acres.

Formula

mi² = ha × 0.00386102

1 ha = 0.00386102 mi²
1 mi² = 258.999 ha

Worked example

To convert 1 ha, multiply by 0.00386102: 1 × 0.00386102 = 0.00386102 mi².

Frequently asked questions

How many square miles are in a hectare?

There are 0.00386102 square miles in one hectare. To convert any amount, multiply the number of hectares by 0.00386102.

How do I convert square miles back to hectares?

Divide instead of multiplying, or equivalently multiply by 258.999. One square mile is 258.999 hectares.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between hectares and square miles is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Hectares: exactly 10,000 m², the metric standard for farmland and land registry. Square Miles: used for land and territory area in the US and UK. One square mile is exactly 640 acres.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units