How to calculate square footage
Updated on June 30, 2026 · by Rafael Rossi
A square meter (m²) is the area of a square 1 m on each side — the unit for rooms, lots, flooring and paint. For a rectangular space, it's a simple multiplication.
The formula
area = length × width
A room 5 m × 4 m is 5 × 4 = 20 m². For several identical rooms, multiply by the count.
Watch the units
Measure everything in meters before multiplying. Centimeters give cm² (and 1 m² = 10,000 cm²). Mixing units is the most common mistake.
L-shaped or irregular spaces
Split into rectangles, find each area and add them. To subtract a gap (a column, a built-in), compute its area and subtract.
What you'll use it for
- Flooring/tiles: area ÷ area per piece, plus ~10% waste.
- Paint: add wall areas and divide by the can's coverage.
- Real estate: price per m² compares different-sized properties.
m² and ft²
Feet measurements give ft². To convert: 1 m² = 10.76 ft². One hectare is 10,000 m².