Convert between square metres, acres, hectares and square feet instantly.
Area units convert by the square of the corresponding length factor, which is the single most important thing to know here and the source of nearly every error. One metre is 3.28 feet, but one square metre is 10.76 square feet, not 3.28.
A room 4 m by 5 m is 20 m2. In feet that is 13.12 by 16.40, which is 215.3 ft2 — and 215.3 is 20 x 10.76, not 20 x 3.28. The same logic means doubling the dimensions quadruples the area. A 3 m by 3 m room is 9 m2; a 6 m by 6 m room is 36 m2, four times as large despite the sides only doubling.
This matters practically when estimating materials. Increasing a patio's dimensions by 20% increases the paving needed by 44%, not 20%, and the same relationship governs paint, flooring, turf and tiles.
| From | To | Multiply by |
|---|---|---|
| Square metres | Square feet | 10.7639 |
| Square feet | Square metres | 0.092903 |
| Acres | Hectares | 0.404686 |
| Hectares | Acres | 2.47105 |
| Acres | Square feet | 43,560 |
| Square kilometres | Square miles | 0.386102 |
| Square yards | Square metres | 0.836127 |
The acre is historically the area a team of oxen could plough in a day, standardised as one chain by one furlong — 66 by 660 feet, giving 43,560 ft2. Its awkwardness is a direct consequence of that agricultural origin. It remains standard for land in the US, UK and India.
The hectare is far cleaner: 100 m by 100 m, exactly 10,000 m2, and 100 hectares to the square kilometre. It is the metric standard for land almost everywhere else. A hectare is about 2.47 acres, so a rough conversion is to multiply hectares by 2.5.
For scale: a football pitch is roughly 0.7 hectares or 1.75 acres, and a square kilometre is 100 hectares or about 247 acres.
India and parts of South Asia use several traditional units whose size varies by state, which makes them a frequent source of confusion in property transactions.
| Unit | Approximate size | Where used |
|---|---|---|
| Bigha | 1,500-6,772 m2 (varies widely) | North and East India, Nepal |
| Guntha | 101.17 m2 (1/40 acre) | Maharashtra, Karnataka |
| Cent | 40.47 m2 (1/100 acre) | South India |
| Ground | 222.97 m2 (2,400 ft2) | Tamil Nadu |
| Marla | 25.29 m2 | Punjab, Pakistan |
| Kanal | 505.86 m2 (20 marla) | Punjab, Pakistan |
The bigha deserves particular caution — it has no standard value and ranges by more than a factor of four between states. Any land document quoting bighas should also state the local conversion, and a survey record in square metres or square feet is the figure to trust.
When buying flooring, tiles or paint, the converted area is only the starting point. Add 5-10% for waste from cuts and breakage, more for diagonal or patterned layouts where offcuts are harder to reuse. Paint coverage is usually quoted per litre per coat — a typical figure is 10-12 m2 per litre — so a 40 m2 wall needing two coats requires around 7 litres, not 3.5. Subtract large openings such as windows and doors, but do not bother subtracting small ones; the waste allowance covers them.
Because area scales as the square of length. A metre is 3.28 feet, so a square metre is 3.28 squared, which is 10.76 square feet. Applying the linear factor to an area is the most common conversion error there is.
43,560. The figure comes from the acre's definition as one chain by one furlong — 66 feet by 660 feet — which is why it is not a round number.
A hectare is 10,000 square metres, a 100 m square. An acre is 4,046.86 square metres. One hectare is about 2.47 acres, so multiplying hectares by 2.5 gets you close enough for most purposes.
There is no single answer — it ranges from about 1,500 to 6,772 square metres depending on the state. Always confirm the local conversion against an official survey record before relying on a figure quoted in bighas.
Add 5-10% to the calculated area for cutting waste and breakage, and more like 15% for diagonal or patterned layouts. It is also worth having spare from the same batch, since later production runs may differ slightly in colour.