This room area calculator measures floor area and perimeter for five common shapes: rectangle, square, circle, triangle and an L-shape made from two rectangles. It is a practical starting point for flooring, paint planning, rugs and room layout decisions.
You can work in feet or metres. The result gives the area in both square feet and square metres, together with the perimeter in the unit selected, so the figures are easy to reuse in other project calculations.
Room Area Calculator
Calculate floor area and perimeter for common room shapes, in square feet and square metres.
Your Result
Area
Area
Perimeter
How to Use This Tool
- Select the room shape that best matches the floor.
- Choose feet or metres as the measurement unit.
- Enter only the dimensions requested for that shape, such as length and width, radius, base and height, or both rectangles for an L-shape.
- Select Calculate Area.
- Use the displayed area and perimeter for your next project estimate.
Accurate measurements matter more than decimal places. Measure the longest points, note any alcoves or bays separately, and split complicated floors into simple shapes. For circles and triangles, the result also depends on using the radius and perpendicular height described by the tool.
Use the figure with the Flooring Calculator or the Paint Calculator, and browse our free online tools for the rest of the project.