A hectare is bigger than an acre. One hectare is 10,000 square metres, which is about 2.47 acres. One acre is 4,046.86 square metres, which is about 0.405 hectares. So a hectare is roughly two and a half acres.
This guide shows how big each unit really is, how to convert between them in one step, and how they compare with a football pitch and an American football field. The figures come from the BIPM SI Brochure, NIST, Britain’s Weights and Measures Act 1985, the IFAB Laws of the Game and the NFL Rulebook.
| Acre | Hectare | |
|---|---|---|
| Symbol | often written “ac” | ha |
| In square metres | 4,046.86 m² | 10,000 m² |
| In square feet | 43,560 sq ft | about 107,639 sq ft |
| In square yards | 4,840 sq yd | about 11,960 sq yd |
| In the other unit | 0.405 ha | 2.471 acres |
| As a square | about 63.6 m (208.7 ft) a side | 100 m (328.1 ft) a side |
| System | Imperial and US customary | Metric (used with the SI) |
Which is bigger, an acre or a hectare?
The hectare. You can fit almost two and a half acres inside one hectare. If you lay out each one as a square, the hectare square is 100 metres on each side. The acre square is only about 63.6 metres on each side.
What is a hectare?
A hectare is a square 100 metres long and 100 metres wide. That makes 10,000 square metres. There are 100 hectares in one square kilometre.
The name comes from “hecto” (100) and “are”. An are is 100 square metres, so a hectare is 100 ares. You can read more about prefixes like hecto in our guide to metric prefixes.
The hectare is not an SI unit, but it is part of the metric family. The BIPM SI Brochure (9th edition, version 4.01, June 2026) lists it in Table 8 as 1 ha = 1 hm² = 10⁴ m². It also notes that the international committee for weights and measures (CIPM) adopted the are and the hectare in 1879 for land area. The symbol is a lower-case ha.
What is an acre?
An acre is 43,560 square feet, or 4,840 square yards. In metric, it is exactly 4,046.856 422 4 square metres. There are 640 acres in one square mile.
An acre has no fixed shape. Any piece of land with that area is an acre. The old units explain the odd number. Britain’s Weights and Measures Act 1985 defines a chain as 22 yards and a furlong as 220 yards. A strip one chain wide and one furlong long is 22 × 220 = 4,840 square yards, which is one acre.
How to convert acres to hectares (and back)
You only need one number for each direction:
- Acres to hectares: multiply by 0.404 686. For a quick estimate, multiply by 0.4.
- Hectares to acres: multiply by 2.471 05. For a quick estimate, multiply by 2.5.
Example: a 5-acre plot is 5 × 0.404 686 = 2.02 hectares. A 20-hectare farm is 20 × 2.471 05 = 49.4 acres. The quick estimates are close but run a little high or low, so use the full number for anything you sign or pay for. See our guide to significant figures if you are not sure how far to round.
| Acres | Hectares | Hectares | Acres | |
|---|---|---|---|---|
| 1 | 0.405 | 1 | 2.471 | |
| 2 | 0.809 | 2 | 4.942 | |
| 5 | 2.023 | 5 | 12.355 | |
| 10 | 4.047 | 10 | 24.711 | |
| 20 | 8.094 | 20 | 49.421 | |
| 50 | 20.234 | 50 | 123.553 | |
| 100 | 40.469 | 100 | 247.105 |
How big is an acre or a hectare in real life?
Sports fields make a good picture, because their sizes are written down in the rules.
- Football (soccer) pitch: Law 1 of the IFAB Laws of the Game allows a pitch from 90 to 120 m (100 to 130 yd) long and 45 to 90 m (50 to 100 yd) wide. For international matches it must be 100 to 110 m long and 64 to 75 m wide. That puts an international pitch at about 0.64 to 0.825 hectares, or 1.6 to 2.0 acres.
- Using the metric limits, the smallest full-size pitch is almost exactly one acre. At 90 × 45 m it covers 4,050 m², just 3 m² more than an acre.
- Using the metric limits, the biggest pitch is just over one hectare. At 120 × 90 m it covers 10,800 m², or 1.08 ha. (The Law also gives limits in yards, which work out very slightly bigger.)
- American football field: the 2026 NFL Rulebook sets the field at 360 feet long and 160 feet wide, end zones included. That is 57,600 sq ft: about 1.32 acres or 0.54 hectares.
Where are acres and hectares used?
Countries that use the metric system usually give land area in hectares, or in square metres for small plots. The acre is still the usual land unit in the United States, and you will also see it in Britain.
In British law the two units have a different status. Schedule 1 of the Weights and Measures Act 1985 lists the hectare with the metric units in Part II. The acre sits in Part VI, a list of units that “may not be used for trade except as supplementary indications”. So in trade, the acre may only be shown alongside the metric figure. This limit is about trade; it does not stop people talking about acres.
Some places also use local land units, such as the bigha in parts of South Asia. Their size can differ from place to place, so there is no single bigha-to-acre or bigha-to-hectare figure. Ask the local land records office for the value used in your area.
Is a US survey acre different?
Only by a tiny amount, and it is no longer meant to be used. The old US survey foot was a little longer than the normal (international) foot. NIST’s conversion table gives the acre based on the survey foot as 4,046.873 m², about 0.016 m² (0.17 sq ft) more than the international acre.
NIST says 31 December 2022 was the last day the US survey foot should be used. From 1 January 2023 it was deemed obsolete and replaced by the international foot. NIST adds that the acre was once defined only in terms of the survey foot. It now also has a definition in terms of the international foot. For everyday land, a gap of 0.17 sq ft per acre is far too small to matter.
Common mistakes
- Thinking a hectare is 1,000 m². It is 10,000 m² (100 m × 100 m).
- Multiplying the wrong way. Going from acres to hectares, the number gets smaller (× 0.405). Going from hectares to acres, it gets bigger (× 2.471).
- Writing “Ha” or “HA”. The symbol is a lower-case “ha”.
- Expecting an acre to be a square. An acre is an area, not a shape. A long thin strip can be one acre too.
- Treating a bigha like a fixed unit. Check the local value first.
More unit comparisons: nautical mile vs mile and long ton vs short ton vs metric tonne.
Frequently asked questions
How many acres are in a hectare?
About 2.471 acres. For a quick estimate, use 2.5.
How many hectares are in an acre?
About 0.405 hectares. For a quick estimate, use 0.4.
How many square metres are in an acre?
4,046.856 422 4 m², usually rounded to 4,047 m².
How many square feet are in a hectare?
About 107,639 sq ft. An acre is 43,560 sq ft.
Is a football pitch bigger than an acre?
Yes. Every full-size pitch within Law 1 is at least about one acre, and an international pitch is about 1.6 to 2.0 acres. Smaller youth and small-sided pitches fall outside these full-size limits.
How many hectares are in a square kilometre?
100 hectares. A square mile is 640 acres, or about 259 hectares.
Justwebworld has published guides since 2012. How we write and update articles Report an error
