Room area calculator
- Area (metric)
- 14.7 m²
- Area (imperial)
- 158.23 sq ft
- With allowance
- 16.17 m² / 174.1 sq ft
Results update as you type.
Area formulas
| Shape | Formula | Example |
|---|---|---|
| Rectangle | length × width | 4.2 × 3.5 = 14.7 m² |
| L-shape | (a × b) + (c × d) | (5 × 4) + (2 × 3) = 26 m² |
| Triangle | base × height ÷ 2 | 6 × 3 ÷ 2 = 9 m² |
| Circle | π × diameter² ÷ 4 | π × 2² ÷ 4 ≈ 3.14 m² |
Square feet are converted with the exact definition of the foot, 0.3048 m, from the NIST Guide to the SI. Related tools: stair calculator and roof pitch calculator. For house types and room layouts by era, see the house styles guide.
Questions
How do I calculate the area of a room?
For a rectangular room, multiply length by width. A room 4.2 m by 3.5 m is 14.7 m². Measure wall to wall at floor level and use the same unit for both sides.
How do I measure an L-shaped room?
Split it into two rectangles that do not overlap, find the area of each, and add them together. The calculator does this when you choose L-shape.
How many square feet are in a square meter?
One square meter is about 10.764 square feet, because a foot is exactly 0.3048 m and 1 ÷ 0.3048² ≈ 10.7639.
How much extra flooring should I order?
Installers commonly add a margin for cuts and mistakes. The right figure depends on the material, pattern and room shape, so check the manufacturer's guidance; the calculator lets you add 5, 10 or 15 percent.