Hectares to Acres Converter
Enter an area in hectares or acres and this converter fills in the other unit immediately, plus square meters, square feet, square miles, and the length of a side if the plot were a perfect square. Switch the direction with the mode selector to go from acres to hectares instead.
How to convert hectares to acres
One hectare is defined as 10,000 square metres. One international acre is defined as exactly 4,046.8564224 square metres. Dividing one by the other gives the exact conversion factor: 1 ha = 2.4710538147 ac. To convert any number of hectares to acres, multiply by 2.4710538147. To go the other way, divide the acre value by the same factor (or multiply by 0.40468564). The factor is internationally agreed and does not vary by country or time period, so the same number applies everywhere.
Hectares versus acres: which unit to use
Hectares (ha) are the standard unit for land measurement in countries that use the metric system, which means most of the world. They are used in land registration, agricultural surveys, forestry, environmental reporting, and planning applications in Europe, Australia, Canada, and most of Asia and Africa. Acres remain the legal and customary standard in the United States, and are still used informally in the UK, Ireland, and some Caribbean and African nations that inherited British land law. When dealing with international land transactions or comparing datasets from different countries, you will frequently need to convert between the two. The square metre and square foot are used for smaller areas such as building footprints and individual lots, while square miles (640 acres, 258.999 ha) or square kilometres are used for very large regions.
Real-world size references for hectares and acres
A single hectare (2.47 ac) is a square 100 metres on each side. Useful benchmarks: an international soccer pitch is roughly 0.71 ha (1.76 ac); a standard American football field including end zones is about 0.536 ha (1.32 ac); a standard UK allotment is 250 m^2, so 40 allotments equal 1 ha. One acre is about 90% of an American football field. Central Park in New York City is 341 ha (843 ac). An average UK farm covers roughly 87 ha (215 ac); the average US farm is about 179 ha (442 ac). A square mile of land (a township section) equals exactly 640 acres or about 259 ha. These comparisons help translate abstract numbers into something you can visualise on the ground.
Precision and rounding in land area conversions
The exact factor is 2.4710538147 ac per ha. Using only 2.471 introduces an error of about 0.0001 per cent per hectare, which is negligible for most practical purposes but may matter in large-scale agricultural contracts, legal surveys, or GIS datasets covering thousands of hectares. The precision selector on this calculator lets you choose 2, 4, 6, or 8 decimal places. For everyday use 2-4 decimal places is sufficient; for survey-grade work use 6-8. Note that GPS-derived field boundaries typically carry their own positional uncertainty of 1-5 metres per boundary point, which translates to much larger area uncertainty than any rounding in the conversion factor.
Common hectares to acres conversions
| Hectares (ha) | Acres (ac) | Square meters (m^2) | Typical land use context |
|---|---|---|---|
| 0.01 | 0.0247 | 100 | Large garden or allotment |
| 0.05 | 0.1236 | 500 | Suburban residential lot |
| 0.1 | 0.2471 | 1,000 | Small development block |
| 0.5 | 1.2355 | 5,000 | Small hobby farm or vineyard plot |
| 1 | 2.4711 | 10,000 | Standard benchmark (one ha) |
| 2 | 4.9421 | 20,000 | Small market garden |
| 5 | 12.3553 | 50,000 | Small arable field |
| 10 | 24.7105 | 100,000 | Medium farm field |
| 40 | 98.842 | 400,000 | US family farm (40 acres / 162 ha common allocation) |
| 100 | 247.105 | 1,000,000 | Large commercial farm block |
| 259 | 640 | 2,590,000 | 1 square mile (section) |
| 1000 | 2471.05 | 10,000,000 | Large station or estate |
Quick reference for land areas frequently used in agriculture, real estate, and environmental planning.
Frequently asked questions
How many acres is 1 hectare?
1 hectare equals exactly 2.4710538147 acres (international definition). For everyday use, 2.471 acres per hectare is a convenient approximation accurate to 0.001 per cent.
How do I convert acres to hectares?
Divide the number of acres by 2.4710538147, or equivalently multiply by 0.40468564. For example, 10 acres is 10 / 2.4711 = 4.047 ha. Use the mode selector on this calculator to switch to acres-to-hectares mode.
What is 5 hectares in acres?
5 hectares x 2.4710538147 = 12.3553 acres. That is roughly the size of a small arable field or 9 standard soccer pitches.
What is 100 acres in hectares?
100 acres / 2.4710538147 = 40.4686 hectares. This is a common farm block size in the United States, sometimes referred to informally as a quarter section (a section being 640 acres = 259 ha).
How many hectares are in a square mile?
1 square mile = 640 acres = 640 / 2.4710538147 = 258.999 ha, usually rounded to 259 ha. The slight deviation from 259 is because the conversion factor between the metric and imperial inch is exact but not a tidy decimal.
Why do some countries use hectares and others use acres?
Hectares belong to the metric system, which most countries adopted after the Treaty of the Metre in 1875. Acres are part of the older Imperial and US Customary systems. The United States never formally adopted metric for land measurement, and the UK retains acres informally despite legally switching to metric. International agri-trade and environmental reporting typically use hectares because they link directly to square metres and square kilometres.
What is the square side length and why is it useful?
The square side length is the side of a perfect square that has the same area as your input. For example, 1 ha is a 100 m x 100 m square, and 10 ha is a 316 m x 316 m square. This is useful for visualising a parcel's footprint even when its actual shape is irregular, and for quick mental estimation of fencing perimeters under a square assumption.
Sources
- International Bureau of Weights and Measures (BIPM), The International System of Units (SI), 9th edition, 2019: definition of the hectare
- US National Institute of Standards and Technology (NIST), Handbook 44, Specifications, Tolerances, and Other Technical Requirements: definition of the international acre