Acres to Hectares Converter
Convert acres to hectares by multiplying by 0.4046856. Includes a land-area conversion table, the history of both units, and reference sizes for farms, football pitches and city blocks.
Acres to hectares
Formula
Multiply by 0.4046856.
Roughly, one hectare is two and a half acres, and one acre is a little over four tenths of a hectare. For a quick field estimate, multiplying acres by 0.4 is within 1.2% of the true figure.
Worked example
Convert a 120 acre farm:
And a 2.5 ha plot back to acres:
Conversion table
| Acres | Hectares (ha) |
|---|---|
| 1 | 0.4046856 |
| 2 | 0.8093713 |
| 5 | 2.023428 |
| 10 | 4.046856 |
| 20 | 8.093713 |
| 40 | 16.18743 |
| 50 | 20.23428 |
| 100 | 40.46856 |
| 250 | 101.1714 |
| 500 | 202.3428 |
| 1,000 | 404.6856 |
Where the units come from
A hectare is simply 100 ares, or a square 100 m on a side — 10,000 m² exactly. It is metric, tidy, and the standard unit for land area almost everywhere.
An acre is medieval English, and originally meant the area one man with one ox could plough in a day. That history is why it is not a square: the traditional acre is one chain by one furlong, or 22 yards by 220 yards, which works out to 4,840 square yards or 43,560 square feet. In SI terms that is 4,046.856 m².
So an acre is a long thin strip, not a square — a detail that still shows up in old field boundaries.
Reference land areas
- Football pitch (FIFA standard) — 0.714 ha = 1.76 acres
- Small allotment — 0.025 ha = 0.062 acres
- Trafalgar Square — about 1.2 ha = 3.0 acres
- Average UK farm — 87 ha = 215 acres
- Average US farm — 183 ha = 452 acres
- Central Park, New York — 341 ha = 843 acres
- Square kilometre — 100 ha = 247.1 acres
FAQ
How many hectares is 1 acre? 0.4046856 ha.
How many acres is 1 hectare? 2.471054 acres.
How many acres in a square mile? 640 — which is why US land survey sections are exactly one square mile.
How many square metres in an acre? 4,046.856 m².
Is an acre a square? No. Traditionally it is one chain by one furlong, 22 × 220 yards. A square acre would be about 63.6 yards on a side.