How to measure a room in square feet and square metres

Flooring is sold by the square metre in some shops and by the square foot in others. Property listings mix the two. Measuring a room once and converting carefully saves both money and a second trip to the shop.

Measure the floor

1. Measure the length and the width at floor level, wall to wall, in the same unit.
2. Measure twice; rooms are rarely perfectly square, so use the larger figure.
3. Multiply length by width.

A room 12 ft by 14 ft is 168 square feet. A room 4 m by 5 m is 20 square metres. If you measured in feet and inches, convert the inches to a decimal first: 12 ft 6 in is 12.5 ft.

Convert the area

• 1 square metre = 10.764 square feet
• 1 square foot = 0.0929 square metres

So 168 sq ft = 15.6 m², and 20 m² = 215.3 sq ft. The Area Converter handles square metres, square feet, square yards, acres and hectares.

The most common mistake

Converting the lengths with a linear factor and then forgetting to square it. A metre is 3.28 feet, but a square metre is 3.28 × 3.28 = 10.76 square feet, not 3.28. Either convert both sides first and then multiply, or multiply first and use an area conversion. The Length Converter does the first approach; the Area Converter the second.

Also watch the phrasing: “10 feet square” describes a square 10 feet on each side, which is 100 square feet, while “10 square feet” is a small area about the size of a doormat or two.

L-shaped and irregular rooms

Split the room into rectangles, measure each, and add them up. For an L-shaped room, one rectangle for the main part and one for the leg. Subtract fixed units such as kitchen cabinets or a built-in bath if the flooring will not go under them.

How much flooring to buy

• Straight-laid floors: add about 10% for cutting and waste.
• Diagonal or herringbone patterns: add 15% or more, because more pieces are cut at the edges.
• Round up to whole packs, and keep a spare pack from the same batch for future repairs.

Example: 15.6 m² plus 10% = 17.2 m². If packs cover 2.2 m² each, buy 8 packs (17.6 m²).

Property listings

Advertised floor areas may be measured differently: some include internal walls and stairwells, others only usable floor. Different countries and agents use different rules, so compare like with like and measure yourself before relying on a figure for pricing.

For walls rather than floors, see how much paint you need and how many rolls of wallpaper. For land areas, see acres, hectares and land units.