Square Feet to Square Metres

Square feet and square metres are the two units nearly every property transaction and construction drawing is quoted in, and switching between them is one of the most common conversions there is. The factor is exact, not approximate: one square foot is 0.09290304 square metres, because the foot is defined as exactly 0.3048 metres and 0.3048² = 0.09290304.

Enter a figure in square feet and the converter returns square metres to seven significant figures, along with square centimetres, square yards, square millimetres, acres and marla for context.

The two ways to do it, and why one is safer

You can multiply by 0.09290304 or divide by 10.7639104. Both give the same answer, but multiplying by the smaller number is the one to reach for when you are working without a calculator. Dividing by 10.7639104 in your head invites errors, and a slip here is expensive: getting the direction wrong on a 2,000 square foot house misstates it by roughly 1,800 square metres.

A useful bracket to sanity-check with: one square metre is a little under eleven square feet. So a 1,000 square foot area should come out just under 93 square metres. If your answer is in the hundreds for a figure in the thousands, you have multiplied when you should have divided.

Where this conversion actually comes up

Floor plans from most of the world outside the US and UK are drawn in square metres, while the same property marketed to an international buyer is often advertised in square feet. Builders' rates are quoted per square foot in some markets and per square metre in others, so comparing two quotes means converting one of them first.

Flooring, tiling and paint coverage are the other frequent case. A box of laminate flooring is usually labelled with its coverage in square metres even in countries that sell houses in square feet, and paint coverage is nearly always given as square metres per litre.

Worked examples

• 1,000 ft² = 92.90304 m² — a common apartment size
• 1,200 ft² = 111.4836 m²
• 2,000 ft² = 185.80608 m² — a typical three-bedroom house
• 2,722.5 ft² = 252.929 m² — a 10 marla plot at the traditional standard
• 43,560 ft² = 4,046.8564 m² — exactly one acre

Notice the last line: an acre is 4,046.86 square metres, which is why the acre is not a round number in metric and why land registries in metric countries use hectares — 10,000 square metres — instead.

Avoid the classic mistakes

Confusing feet with square feet. Multiplying a length in feet by 0.3048 converts the length to metres; multiplying an area in square feet by 0.09290304 converts the area to square metres. Mixing the two converts a 100 foot wall into 92.9 square metres, which is meaningless.

Rounding the factor too early. Using 0.093 instead of 0.09290304 introduces an error of about 0.1%, which is 2 square metres on a 2,000 square foot house — small, but avoidable.

Converting when you should not. If both figures are already in square feet, there is nothing to convert. This sounds obvious and still causes more errors than either of the above.