Square footage calculator (room area)
Enter width and length to get the area in square feet and square meters, adding several rooms at once. Example: a 10 × 12 ft bedroom is 120 sq ft.
Area = length × width. For L-shaped spaces, add the areas of each rectangle. 1 m² = 10.76 ft².
How the calculation works
A square meter (m²) measures area: how much space a surface takes up. For a rectangular space, multiply the two sides, always in the same unit:
area = length × width
A room 5 m by 4 m is 5 × 4 = 20 m². For several identical rooms, multiply by their count.
Watch the units
Measuring in centimeters yields cm² — and 1 m² = 10,000 cm². Safest is to convert everything to meters first: 250 cm = 2.5 m.
L-shaped or irregular rooms
Split the space into rectangles, find each area and add them. To remove a gap (a column, a built-in), compute its area and subtract.
What you need the area for
- Flooring/tiles: area ÷ area of each piece, plus ~10% waste.
- Paint: add the wall areas and divide by the can's coverage.
- Rent/real estate: price per m² compares properties of different sizes.
Quick conversion
1 m² = 10.76 ft² and 1 m² = 10,000 cm². One hectare is 10,000 m².
Examples
- Room 6 m × 3.5 m: 6 × 3.5 = 21 m².
- 3 identical bedrooms of 3 m × 3 m: 9 m² × 3 = 27 m².
Frequently asked questions
How do I calculate an L-shaped room?
Split it into rectangles, find each area and add them. That is what builders do.
Meter vs square meter?
A meter measures length (a line); a square meter measures area (a surface). You get m² by multiplying two lengths.
How to convert m² to hectares?
1 hectare = 10,000 m². (The Brazilian "alqueire" varies by region.)
Should I add waste when buying flooring?
Yes. Add 10% (or more for large pieces or diagonal layouts) to cover cuts and breakage.
How do I calculate an L-shaped room?
Split it into two rectangles, compute each and add. Alternatively, compute the full bounding rectangle and subtract the missing piece.
How much extra flooring should I buy?
10% for straight laying and 15–20% for diagonal patterns. Buy all boxes from the same batch and keep leftovers.
What is the difference between usable and total area?
Usable area is the floor you actually walk on. Total area adds the private area plus your share of common spaces — and it is usually the advertised figure.
How do I convert square meters to square feet?
Multiply by 10.76. A 12 m² bedroom is about 129 ft². Do not use the linear factor (3.28) — for area it is squared.
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Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources