A familiar situation
Estimate floor area from room dimensions before planning flooring or paint quantities.
How to use this calculator
- Enter shape, length / radius / parallel side a, width / height / parallel side b and the remaining inputs.
- Select Calculate to see the answer and its breakdown.
- Keep a scenario, change an input and compare the results.
Use consistent units and check the assumptions below before applying the result.
How area is calculated
Rectangle area is lw; triangle area is bh/2; circle area is πr²; trapezoid area is (a+b)h/2 for parallel sides a and b. For the trapezoid, h is the perpendicular distance between its parallel sides, not the sloping side. Use matching length units throughout so the result is consistently in square metres, square centimetres, or another squared unit. A 4 m by 6 m rectangle has area 24 m².
Rectangle lw; triangle bh/2; circle πr²; trapezoid (a+b)h/2.A 4 m by 6 m rectangle has area 24 m².
Assumptions & useful context
The result depends on the values you enter and the method described above. Displayed numbers may be rounded; calculations use the unrounded values. Check that this model matches your situation before relying on it.
Frequently asked questions
Do I enter a circle’s diameter?
Enter its radius.
Why is area measured in square units?
Multiplying two lengths creates a squared unit such as cm².