m² Area Calculator

Tiles, paint, flooring and floor plans are all sold or drawn in square meters across most of the world, so that is the number you usually need, even if your tape reads in centimeters or feet. Each length here has its own unit menu and starts on meters, and the headline answer stays in m² whatever you pick.

Formula

A = l × w

A

the area in square meters

l

the length in meters

w

the width in meters

A wall is the same sum with its openings taken off: A = w × h − openings.

Length times width

Measure both sides in meters and multiply. A room of 4.2 m by 3.5 m covers 14.7 m², or about 158.23 ft². If your tape reads in centimeters, you can enter 420 cm and 350 cm, and the calculator converts them for you. By hand, divide by 100 before multiplying. Multiplying 420 by 350 gives 147,000, which is square centimeters and not square meters.

A measurement in feet works as well. A room of 14 ft by 11 ft comes to about 14.31 m².

Wall area in m²

For a wall, multiply its width by its height, then take off the doors and windows. Take a wall 5 m wide and 2.4 m high, which is 12 m² in all. A door of 0.9 m by 2.1 m is 1.89 m², and a window of 1.2 m by 1.2 m is 1.44 m². Those openings total 3.33 m², which leaves 8.67 m² to paint or tile.

To cover a whole room, use the distance around the room as the width. The 4.2 m by 3.5 m room has a perimeter of 15.4 m, so with a 2.4 m ceiling, its walls come to 36.96 m². Taking off the same door and window leaves 33.63 m². For two coats of paint, double that to 67.26 m², then divide by the coverage on the tin. At a stated 10 m² per liter, you would need about 6.7 liters.

• Wall area = width × height − openings
• Room walls = perimeter × height − openings

Tile area in m²

Find the area to tile, then the area of one tile, and divide. For a floor of 3 m by 2 m, the area is 6 m². A 30 cm square tile covers 0.3 × 0.3 = 0.09 m², so the floor takes 6 ÷ 0.09 ≈ 66.67 tiles, which rounds up to 67.

Tiles get cut and broken, so buy extra. A 10% allowance is a common starting point, and a diagonal pattern usually needs more. On this floor, that makes 6.6 m², or about 73.33 tiles, so 74 in all. Boxes are often labeled with the m² they cover, which saves counting single tiles.

Converting square meters

Area conversions use the square of the length conversion. A meter is 100 cm, so a square meter is 100 × 100 = 10,000 cm². The table gives the units this calculator shows. A hectare is a square of 100 m by 100 m.

Frequently asked questions