Measurement tools
Square Metre Calculator
Add up rectangles, circles, triangles and L-shapes into total square metres.
How this calculator works
Add one section per part of your space: rectangles for rooms, circles for round features, triangles for angled corners and L shapes for combined rooms. The calculator totals every section into square metres, with square feet shown for reference.
For a rectangle, multiply length by width. A circle is pi times the radius squared. A triangle is half of base times height. L shapes split into two rectangles that the calculator adds together.
Measure in metres at the widest points, and when a room is slightly irregular, round up rather than down. Materials are bought with waste allowances on top of true area.
| Shape | Formula |
|---|---|
| Rectangle | length × width |
| Circle | π × (diameter ÷ 2)² |
| Triangle | ½ × base × height |
| L shape | main rectangle + leg rectangle |
Frequently asked questions
How do I calculate square metres of a room?
Measure the length and width in metres at the widest points and multiply them. A 4.2m by 3.5m bedroom is 14.7 square metres. For L shaped rooms, split the space into two rectangles and add them, or use the L shape section here.
How many square feet in a square metre?
One square metre is 10.764 square feet. The calculator shows both, handy when comparing against American product listings.
How do I measure an odd shaped area?
Break it into simple shapes: rectangles, triangles and parts of circles. Add a section for each piece and the calculator totals them. Getting within a few percent is fine for ordering materials.
Do I measure walls or floor for a room?
Floor area is length times width of the floor. Wall area for painting is the perimeter times wall height. If you are painting, our paint calculator handles walls, doors and windows directly.
Related calculators
Ready to get this job done?
Tell us about your project and hear from up to 3 local pros within 1 business day. Free and no obligation.