Area Converter

Convert between square feet, square metres, square yards, acres, hectares and square miles.

Draft — figures checked, awaiting an editorial read. Not indexed.

Formula: Result = amount × (factor of source unit ÷ factor of target unit), with every factor expressed in square metres.

What this calculates

This converts area between the units used for rooms, plots and land: square feet and square metres at the building scale, acres and hectares at the land scale. The relationship people find least intuitive is that area factors are the *squares* of the length factors. A metre is 3.28 feet, but a square metre is 10.76 square feet, because both dimensions scale. That squaring is why doubling a room's dimensions quadruples its floor area, and why land prices per acre and per hectare differ by a factor of 2.47 rather than the 1.6 you might expect from the linear units.

How it works

Every unit carries a factor in square metres, derived by squaring the corresponding length factor. A square foot is 0.3048² = 0.09290304 square metres, exactly. The two land units are historical rather than derived: an acre is defined as 4,840 square yards, which works out to 4,046.8564224 square metres, while a hectare is a clean 10,000 square metres — a square 100 metres on a side. That is why they do not convert to a round number of each other.

Worked example

A 1,000 square foot apartment in square metres: 1000 × 0.09290304 = 92.9 square metres. A one acre plot in square feet: 4046.856 ÷ 0.09290304 = 43,560 square feet — a number worth memorising if you deal with land at all. And an acre in hectares: 4046.856 ÷ 10000 = 0.4047, so two and a half acres is almost exactly one hectare.

Common mistakes

Converting area with a linear factor. Multiplying square feet by 0.3048 instead of by 0.3048² gives an answer that is 3.28 times too large and, worse, is the sort of error that survives a quick sanity check. Second, confusing the acre with a specific shape — it is a quantity of area, not a square, and a one acre plot can be any shape at all. Third, mixing up hectares and acres in land listings, where the 2.47× difference is enough to badly misread a price.

Common questions

How many square feet are in an acre?

43,560 square feet exactly, since an acre is defined as 4,840 square yards. It is roughly the size of an American football field without the end zones.

How many square feet in a square metre?

10.7639 square feet. Note this is the square of the linear conversion, not the linear conversion itself.