Acres to Hectares Converter

About the ac to ha calculation

One acre is exactly 0.404686 hectares, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The standard land unit in the US and UK — originally the area one ox team could plough in a day. Exactly 10,000 m², the metric standard for farmland and land registry.

Formula

ha = ac × 0.404686

1 ac = 0.404686 ha
1 ha = 2.4711 ac

Worked example

To convert 1 ac, multiply by 0.404686: 1 × 0.404686 = 0.404686 ha.

Frequently asked questions

How many hectares are in a acre?

There are 0.404686 hectares in one acre. To convert any amount, multiply the number of acres by 0.404686.

How do I convert hectares back to acres?

Divide instead of multiplying, or equivalently multiply by 2.4711. One hectare is 2.4711 acres.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between acres and hectares 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?

Acres: the standard land unit in the US and UK — originally the area one ox team could plough in a day. Hectares: exactly 10,000 m², the metric standard for farmland and land registry.

Sources

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