Acres to Square Metres Converter
1 acre = 4,046.8564224 m² exactly. Type in either box.
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An acre is 4,046.86 square metres
The acre is a medieval English unit and the square metre is a product of the French Revolution, so there was never any reason for them to line up. They do not.
1 acre = 4,046.8564224 m² exactly
The figure is exact despite its length, because the yard has been defined as exactly 0.9144 metres since 1959 and an acre is exactly 4,840 square yards. Everything follows from those two numbers.
For a sense of scale: an acre is about 0.405 of a hectare, or a square roughly 64 metres on each side.
The acre
The acre began as the area a yoke of oxen could plough in a day: a furlong long and a chain wide, or 4,840 square yards. That awkward-looking figure is why the acre converts to no round number of anything metric.
It remains the standard unit for land in the United States, the United Kingdom, India and Bangladesh. An acre is about 40 % of a hectare, or roughly 60 % of a football pitch.
The square metre
The SI unit of area, and the one most of the world uses for rooms, floor plans and small plots. A square metre is a square one metre on each side — roughly the footprint of a dining chair with space to move.
Because area scales with the square of length, doubling a room's dimensions quadruples its area. That relationship trips people up constantly when converting between systems: the conversion factor for square units is the length factor squared.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where area conversions come up
- Property listings. Square feet in the United States, India, Bangladesh and the Gulf; square metres almost everywhere else. The same flat is advertised in both depending on who is selling it.
- Land. Acres in the English-speaking world and South Asia, hectares nearly everywhere else. Farm subsidies, planning applications and land registries rarely agree on which to use.
- Flooring and carpet. Sold by the square metre in Europe and by the square yard or square foot in the United States.
- Paint and materials. Coverage is quoted per square metre or per square foot, so a tin bought abroad needs converting before you know how far it goes.
The trap: area factors are length factors squared
A foot is 0.3048 m, so people reach for 0.3048 when converting square feet. It is wrong. Area scales with the square of length, so the factor is 0.3048 × 0.3048 = 0.09290304.
The same logic runs everywhere. A yard is 3 feet, so a square yard is 9 square feet, not 3. A kilometre is 1,000 metres, so a square kilometre is 1,000,000 square metres. Getting this wrong is the most common mistake in area conversion, and it is easy to catch: if your answer is out by roughly the length factor itself, this is why.
Tips worth knowing
- A hectare is 2.471 acres, and an acre is 0.4047 of a hectare. Neither is a round number, because the acre descends from medieval ploughing and the hectare from the metre.
- An acre is 43,560 square feet. Not round either, and worth memorising if you deal in land.
- 640 acres make a square mile, which is one section in the American survey grid.
- One square metre is 10.764 square feet. Multiplying by ten and adding eight per cent gets you very close in your head.
Values people look up most
Each one opens the converter with the number already in it.
- 0.1 ac to m²
- 0.25 ac to m²
- 0.5 ac to m²
- 1 ac to m²
- 1.5 ac to m²
- 2 ac to m²
- 2.5 ac to m²
- 3 ac to m²
- 4 ac to m²
- 5 ac to m²
- 10 ac to m²
- 15 ac to m²
- 20 ac to m²
- 25 ac to m²
- 50 ac to m²
- 100 ac to m²
- 200 ac to m²
- 500 ac to m²
Quick reference
| Acres | Square metres |
|---|---|
| 0.1 ac | 404.685642 m² |
| 0.25 ac | 1,011.714106 m² |
| 0.5 ac | 2,023.428211 m² |
| 1 ac | 4,046.856422 m² |
| 2 ac | 8,093.712845 m² |
| 5 ac | 20,234.282112 m² |
| 10 ac | 40,468.564224 m² |
| 20 ac | 80,937.128448 m² |
| 50 ac | 202,342.82112 m² |
| 100 ac | 404,685.64224 m² |
| 640 ac | 2,589,988.1103360001 m² |
Questions people ask
How many square metres in an acre?
4,046.8564224 m², exactly.
How big is an acre in metres?
About 64 m by 64 m if it were square. The original acre was long and thin: 20 m by 200 m.
How does an acre compare to a hectare?
An acre is 0.4047 hectares; a hectare is 2.471 acres.
Why is the factor not just the length conversion?
Because area is two-dimensional. A foot is 0.3048 m, so a square foot is 0.3048 × 0.3048 = 0.09290304 m². Using the length factor by mistake is the usual error.