Type the length and width of each room in meters, centimeters, feet or inches. The tool adds them up and shows the total in square meters, square feet and square yards, with a cost estimate if you add a price.
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This square meter calculator is for homeowners, renters, students and tradespeople who need the floor area of a room, a flat or a whole set of rooms. Enter sizes in any common unit and get square meters, square feet and square yards at once, plus a total cost from a price per m².
How Do You Calculate Square Meters?
To calculate square meters, measure the length and width in meters and multiply them. A room 5 m long and 4 m wide is 5 × 4 = 20 m². For several rooms, work out each one and add them: 20 m² plus a 3 m by 2.8 m room of 8.4 m² gives 28.4 m².
What Is a Square Meter?
A square meter (m²) is the area of a square that is 1 meter long on each side, and it is the unit of area in the International System of Units (SI). Flats, floors, plots and building plans in most of the world are sold and drawn in square meters. In the US and for some UK listings, the square foot (ft²) is still common, and carpet is sometimes priced by the square yard.
1 m² = 10.7639 ft² = 1.19599 yd²
1 ft² = 0.09290304 m² (exact, since 1 ft = 0.3048 m)
How Do You Convert cm, Feet or Inches to Square Meters?
Convert each side to meters first, then multiply: divide centimeters by 100, multiply feet by 0.3048 and multiply inches by 0.0254. For example, a 450 cm by 300 cm room is 4.5 m × 3 m = 13.5 m². A 12 ft by 10 ft room is 3.6576 m × 3.048 m = 11.15 m². Converting the area at the end works too: 120 ft² × 0.09290304 = 11.15 m². These factors are exact because the international foot was defined as 0.3048 m in 1959, as recorded by NIST. If you mostly work in feet, our square footage calculator starts from ft², and the feet to meters converter handles single lengths.
How Do You Measure an L-Shaped Room in Square Meters?
Split the L-shaped room into two rectangles, measure each one, and add the two areas. Use Room 1 and Room 2 in this tool for the two parts, and do not count the corner where they overlap twice. The same trick works for a whole home: add each room as its own row, up to six.
Square Meters to Square Feet for Common Room Sizes
Areas from this tool for typical room shapes:
| Room size | Square meters | Square feet |
|---|---|---|
| 3 m × 3 m | 9 m² | 96.9 ft² |
| 4 m × 3 m | 12 m² | 129.2 ft² |
| 5 m × 4 m | 20 m² | 215.3 ft² |
| 6 m × 5 m | 30 m² | 322.9 ft² |
| 10 m × 10 m | 100 m² | 1,076.4 ft² |
When you buy materials, add a little extra for cutting. The flooring calculator and tile calculator add a waste allowance for you.
Worked Example
Priya is pricing new flooring for a living room 5 m by 4 m and a hallway 3 m by 2.8 m, at 25 per m² in her local currency. With meters selected, the tool shows 20 m² + 8.4 m² = 28.4 m², which is 305.7 ft² or 33.97 yd². The cost box shows 28.4 × 25 = 710.00. If she had measured in centimeters, entering 500 by 400 and 300 by 280 with cm selected gives the same 28.4 m².
How Do You Use the Square Meter Calculator?
Pick the unit and price
Choose m, cm, ft or in, and type a price per m² if you want a cost.
Enter each room
Type the length and width of each room. Tap Add room for more, up to six.
Read the total area
The big number is the total in square meters, with each room listed under it.
Check ft², yd² and cost
The boxes show the same area in square feet and square yards, and the total cost.
Frequently Asked Questions
How many square feet are in a square meter?
One square meter is about 10.764 square feet. To change m² to ft², multiply by 10.764. For example, a 20 m² bedroom is about 215.3 ft². To go the other way, multiply square feet by 0.0929.
How do I find square meters of a room in feet?
Measure the length and width in feet, select ft in the tool, and enter them. It converts each side with 1 ft = 0.3048 m. A 12 ft by 10 ft room is 120 ft², which is 11.15 m².
Is m² the same as square meter?
Yes. m² is the symbol for square meter, sometimes written sq m or sqm. It is different from a cubic meter (m³), which measures volume, such as the amount of concrete, soil or water.
How do I calculate the area of a whole house in square meters?
Measure each room separately, add each one as a row in the tool and read the total. Hallways, closets and bathrooms count too. Official floor area figures may also include wall thickness, so they can be a few percent larger.
What does cost per square meter mean?
It is the price for one square meter of material or work, such as flooring at 25 per m². Multiply it by your total area to get the cost. For 28.4 m² at 25 per m², the cost is 710. The tool works with any currency.
Can I use this for a circle or triangle?
This tool is for rectangles. For a triangle, multiply base by height and halve it. For a circle, use π × radius squared, so a 2 m radius gives about 12.57 m². You can split odd shapes into rectangles and add them as rooms.
Sources and Further Reading
- NIST: SI units, area and the square meter
- NIST Office of Weights and Measures: Unit conversion
- BIPM: The International System of Units (SI Brochure)
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Last reviewed: October 2026