Acres to Hectares Converter
Convert acres to hectares — one hectare is about 2.471 acres. Results update as you type; exact factors shown.
One acre is 0.4047 hectares — see the exact factor, not a rounded rule of thumb.
How the acres to hectares converter works
Areas convert through the square metre. Because the inch is exactly 25.4 mm, a square foot is exactly 0.09290304 m², an acre (43,560 square feet) is exactly 4,046.8564224 m² and a square mile (640 acres) is 2,589,988.110336 m². A hectare is 10,000 m² by definition.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common area conversions
| From | To | Units |
|---|---|---|
| 1 ac | 0.4047 ha | acre to hectares |
| 2 ac | 0.8094 ha | acres to hectares |
| 5 ac | 2.0234 ha | acres to hectares |
| 10 ac | 4.0469 ha | acres to hectares |
| 20 ac | 8.0937 ha | acres to hectares |
| 40 ac | 16.1874 ha | acres to hectares |
| 50 ac | 20.2343 ha | acres to hectares |
| 100 ac | 40.4686 ha | acres to hectares |
| 160 ac | 64.7497 ha | acres to hectares |
| 200 ac | 80.9371 ha | acres to hectares |
| 500 ac | 202.3428 ha | acres to hectares |
| 1,000 ac | 404.6856 ha | acres to hectares |
Units in this converter and their exact factors
| Unit | Symbol | One unit in square metres |
|---|---|---|
| square millimetre | mm² | 0.000001 square metre |
| square centimetre | cm² | 0.0001 square metre |
| square metre | m² | 1 square metre |
| hectare | ha | 10,000 square metre |
| square kilometre | km² | 1,000,000 square metre |
| square inch | in² | 0.00064516 square metre |
| square foot | ft² | 0.09290304 square metre |
| square yard | yd² | 0.83612736 square metre |
| acre | ac | 4,046.8564224 square metre |
| square mile | mi² | 2,589,988.110336 square metre |
FAQFrequently asked questions about area conversion
How many hectares is an acre?
0.404686 hectares.
How big is a hectare?
10,000 m² — a square 100 m on each side, or about two and a half acres.
Where did the acre come from?
The area a yoke of oxen could plough in a day: one furlong by one chain.
How many acres in a square mile?
640, which is why a US survey section is 640 acres.
Which do farmers use?
Hectares almost everywhere; acres still in the US, and often in the UK and Ireland alongside hectares.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.