Pick a shape, enter its measurements in metres, and get the area in square metres — plus the same figure in square centimetres and square feet. Handy for working out a room’s floor space, a wall, a garden bed or any surface before buying materials. It runs on your device.
Choose a shape and enter its measurements.
Enter measurements in metres. For irregular spaces, split into shapes and add the areas.
How it works
Each shape uses its standard formula: rectangle is width × length, square is side², circle is π × radius², triangle is ½ × base × height, and trapezoid is the average of the two parallel sides × height. Enter everything in metres and the result comes out in square metres, the unit tradespeople and shops quote.
The conversions are exact: one square metre is 10,000 cm² and about 10.7639 square feet. For an irregular room, split it into rectangles and triangles, work out each piece, and add them up — most real spaces reduce to a few simple shapes.
Practical examples
A room floor
A 4 m × 5 m room is 20 m² — the number you’ll give a flooring or paint shop. That’s also 215.28 square feet if a product is listed in imperial units.
A circular patio
A round patio with a 2 m radius covers about 12.57 m². Circles use π, so a small radius change moves the area quickly — measure carefully.
A triangular gable wall
A gable end 6 m wide and 4 m tall at the peak is ½ × 6 × 4 = 12 m². Add it to the rectangular walls below when estimating paint.
Frequently asked questions
What units should I enter?
Metres. Enter each dimension in metres (a comma or dot for decimals) and the area comes out in square metres, with square centimetres and square feet shown alongside. If you measured in centimetres, divide by 100 first.
How do I find the area of an irregular room?
Break it into simple shapes — rectangles and triangles — calculate each, and add them. An L-shaped room is just two rectangles; an alcove is one more. Most spaces reduce to two or three pieces.
What’s the difference between the circle’s radius and diameter?
The radius is from the centre to the edge; the diameter is all the way across (twice the radius). This tool asks for the radius, so if you measured the diameter, halve it before entering.
How do I convert between m² and square feet?
One square metre is about 10.7639 square feet, so multiply m² by that to get feet, or divide feet by it to get metres. The tool shows both automatically, which helps when a product is sold in imperial units.
Why is 1 m² equal to 10,000 cm² and not 100?
Because area scales with the square of length. A metre is 100 cm, and 100 × 100 = 10,000, so one square metre contains ten thousand square centimetres. It’s a common slip to divide by 100 instead of 10,000.
What is a trapezoid area used for?
Trapezoids (a four-sided shape with two parallel sides) come up in sloped plots, some rooms and roof sections. The area is the average of the two parallel sides multiplied by the perpendicular distance between them.
How much extra should I buy for materials?
This tool gives the exact area; for tiles, flooring or paint add a waste margin (usually 5–10%) on top. Our tile, laminate and paint calculators build that overage in and turn area into packs or litres.
Are my measurements kept private?
Yes. The calculation runs entirely in your browser; nothing is uploaded and analytics never receives your numbers.
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