How to Convert Hectares to Acres (ha to ac)
Area conversions are everyday maths in Singapore property: HDB flats are listed in square metres while condo listings and PSF prices use square feet. This guide shows how to convert hectares into acres by hand, with examples and a quick-reference table.
The conversion
To convert hectares to acres, multiply the value by 2.4710538147. To go the other way, divide by the same number (or multiply by 0.4046856422). For a quick estimate, multiply by about 2.5.
Acres = hectares × 2.4710538147
Worked examples
- 3 ha = 7.4132 ac
- 12.5 ha = 30.8882 ac
- 75 ha = 185.329 ac
Hectares to Acres table
| Hectares | Acres |
|---|---|
| 1 ha | 2.4711 ac |
| 2 ha | 4.9421 ac |
| 5 ha | 12.3553 ac |
| 10 ha | 24.7105 ac |
| 20 ha | 49.4211 ac |
| 25 ha | 61.7763 ac |
| 50 ha | 123.5527 ac |
| 100 ha | 247.1054 ac |
| 250 ha | 617.7635 ac |
| 500 ha | 1,235.53 ac |
| 1,000 ha | 2,471.05 ac |
Common questions
Is ha to ac exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Acres to Hectares converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Background
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
For any value, use the Hectares to Acres Converter or browse all area converters.
Run your own numbers: Hectares to Acres Converter