How many square feet are in a square metre?

10.764. The other way round, one square foot is 0.0929 m².

Is 12 ft 6 in the same as 12.6 ft?

No. There are 12 inches in a foot, so 6 inches is 0.5 ft: 12 ft 6 in is 12.5 ft, or 3.81 m.

Square metres and square feet for rooms: converting both ways

One square metre is 10.764 square feet, and one square foot is 0.0929 square metres. For a room measured in feet and inches, convert each length to metres first (0.3048 m per foot, 0.0254 m per inch), then multiply, and you get the square metres that paint and flooring are sold by.

The figures you need

From	To	Multiply by
Feet	Metres	0.3048
Inches	Metres	0.0254
Metres	Feet	3.281
Square metres	Square feet	10.764
Square feet	Square metres	0.0929

The foot and the inch are defined exactly: 1 ft is 0.3048 m and 1 in is 2.54 cm. The square-foot figures are those squared and rounded.

Why convert the lengths first

Two slips account for most wrong answers.

Feet and inches are not decimals. 11 ft 10 in is 11.83 ft, not 11.10 ft. There are 12 inches in a foot, so each inch is 0.0833 ft.
A length figure used on an area. 120 ft² × 0.3048 is not square metres. An area needs the area figure, 0.0929, because both sides were in feet.

Converting each length to metres before you multiply avoids both. You only ever use the length figures, and the answer comes out in square metres.

Worked example

A room 13 ft 9 in × 11 ft 10 in.

Length: 13 × 0.3048 + 9 × 0.0254 = 3.9624 + 0.2286 = 4.191 m
Width: 11 × 0.3048 + 10 × 0.0254 = 3.3528 + 0.254 = 3.6068 m
Floor area: 4.191 × 3.6068 = 15.116 m²
In square feet: 15.116 × 10.764 = about 162.7 ft²

Check it the other way: 13.75 ft × 11.833 ft = 162.7 ft². The two agree.

Now the slip. Typed as 11.10 ft, the width becomes 3.383 m, 22 cm short, and the floor comes out at 14.179 m² instead of 15.116 m². With 10% extra and packs covering 1.84 m², that buys 9 packs when the room needs 10: one pack short, found on the last row.

Common room sizes

Room in metres	m²	ft²
2.4 × 1.8	4.32	46.5
3 × 3	9	96.9
3.6 × 3	10.8	116.3
4.2 × 3.6	15.12	162.8
5 × 4	20	215.3

Room in feet	ft²	m²
10 × 8	80	7.43
12 × 10	120	11.15
12 × 12	144	13.38
14 × 12	168	15.61
16 × 12	192	17.84

Heights and walls

Convert the height the same way before working out the wall area: an 8 ft ceiling is 8 × 0.3048 = 2.438 m. Then the wall area is the perimeter in metres × the height in metres, as in how to measure a room for paint.

Coverage on a paint tin is in square metres per litre, and flooring packs state their coverage in square metres, so a room worked out in metres can be divided straight into them.

Do it with BuildBatch

Open the Room Refresh Batch and choose “Feet and inches” under “Measured in”. Type the feet and the inches in their own boxes: it converts them, and shows its working in metres. Switching units converts what you have already typed.

What this guide does not cover

Square yards (one is 0.836 m²), if you meet them on an old quote. Volumes, for concrete or screed. Rooms that are not rectangles, which are split into rectangles first; see floor area of an L-shaped room.