Hectare to Acre (ha to ac)
Result
2.471053815 Acre
Formula
ac = ha × 2.471053815
1 ha = 2.471053815 ac, and 1 ac = 0.4046856422 ha.
Area factors are the square of the length factor: 1 ft = 0.3048 m, so 1 ft² = 0.3048² = 0.09290304 m². The acre is 43,560 ft² (4,046.8564224 m²) and the hectare 10,000 m².
Worked examples
- 1 ha × 2.471053815 = 2.4710538 ac
- 10 ha × 2.471053815 = 24.710538 ac
- 100 ha × 2.471053815 = 247.10538 ac
Common mistakes
- Do not apply a length factor to an area: 100 m² is 1,076.39 ft², not 328 ft² (100 × 3.28).
- A plot described as "20 × 30 ft" is 600 ft²; convert each side to metres first or convert the area afterwards — never just one side.
Hectare to Acre table
| Hectare (ha) | Acre (ac) |
|---|---|
| 1 | 2.4710538 |
| 2 | 4.9421076 |
| 5 | 12.355269 |
| 10 | 24.710538 |
| 20 | 49.421076 |
| 50 | 123.55269 |
| 100 | 247.10538 |
| 1,000 | 2,471.0538 |
The units
- Hectare (ha)
- 10,000 m² — a square 100 m on each side.
- Acre (ac)
- 43,560 square feet, exactly 4,046.8564224 m². 640 acres make a square mile.
Sources for these factors
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy