Area conversion
Acres to Hectares (ac to ha)
Compare an acre-based land listing with a hectare-based map or farm record. This page uses acres based on international feet.
1 ac ≈ 0.4047 ha — the calculator keeps the stored factor; this summary may be rounded.
A parcel described as 5 acres
- Starting measurement
- 5 ac
- Converted value (rounded if needed)
- 2.0234 ha
For a historical survey, check which foot definition the original document used. The converter does not read survey metadata or establish a legal boundary.
Acres to Hectares conversion chart
| acres | hectares |
|---|---|
| 1 ac | 0.4047 ha |
| 2 ac | 0.8094 ha |
| 3 ac | 1.2141 ha |
| 4 ac | 1.6187 ha |
| 5 ac | 2.0234 ha |
| 6 ac | 2.4281 ha |
| 7 ac | 2.8328 ha |
| 8 ac | 3.2375 ha |
| 9 ac | 3.6422 ha |
| 10 ac | 4.0469 ha |
| 12 ac | 4.8562 ha |
| 15 ac | 6.0703 ha |
| 18 ac | 7.2843 ha |
| 20 ac | 8.0937 ha |
| 25 ac | 10.1171 ha |
| 30 ac | 12.1406 ha |
| 40 ac | 16.1874 ha |
| 50 ac | 20.2343 ha |
| 60 ac | 24.2811 ha |
| 75 ac | 30.3514 ha |
| 100 ac | 40.4686 ha |
How to convert by hand
Reference relationship (display may be rounded)
1 ac = 0.404685642 ha
- Multiply the amount in acres by the number of hectares per unit.
- Use the calculator for the stored precision; copying a short displayed factor introduces extra rounding.
- Round the result to suit your measurement, after completing the calculation.
Related conversions
About acres and hectares
Area conversions apply to the whole surface or plot. They cannot tell you a room’s width, a boundary length or how much material to allow for cutting waste.
Acre
US / Imperial43,560 square feet, about 0.4047 hectares. The converter uses square international feet.
Commonly used for: Land listings, farm areas and comparisons with hectare-based maps.
Hectare
Metric10,000 square metres, equal in area to a square 100 m on each side. A plot need not be square to be measured in hectares.
Commonly used for: Fields, parks and larger land parcels.
Questions
Does an acre imply a particular plot shape?
No. An acre is an area, not a width or a length. A narrow strip and a roughly square plot can have the same acreage, so you cannot infer boundary lengths from the conversion.
How do I convert hectares back to acres?
Enter the value in the hectares field above to work backwards, or open the Hectares to Acres converter. This uses the stored factors rather than dividing by a rounded number copied from the chart.
Why might the chart and calculator show different decimal places?
The chart uses a compact rounded display. The editable calculator can show up to six decimal places and uses the factors or temperature formulas stored in the library. More displayed digits do not make the original measurement more precise.
Precision and source
The calculator uses stored conversion factors and temperature formulas, then rounds the result for display. A short decimal in a chart is not a claim of exactness. For a calculation with several steps, keep as much precision as the original measurement supports and round at the end.
These acres use international feet. NIST also lists historical US survey-foot measures; use the definition stated in a survey rather than assuming the two are identical.
Reference: NIST SP 811 conversion factors. Its alphabetical tables distinguish unit variants and temperature readings from intervals. Published by ToolsNow. Report a conversion problem.
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