Area Calculator
A simple tool to calculate the area of various shapes like rectangles, triangles, and circles.
How to use this calculator
Choose Rectangle, Triangle, or Circle, enter positive dimensions, then select Calculate area. Keep all measurements in the same unit. The answer uses the square of that unit: meters give square meters (m²), while feet give square feet (ft²).
CHOOSE THE RIGHT MEASUREMENTS
For a rectangle, enter length and width. For a triangle, use the base and its perpendicular height, not the sloping side. For a circle, enter the radius, which is half the diameter. A circle 6 m across has a radius of 3 m.
FORMULAS AND WORKED EXAMPLES
Rectangle: length × width. A room measuring 5 m by 4 m has area 20 m². Triangle: base × height ÷ 2. A triangle with base 6 m and perpendicular height 3 m has area 9 m². Circle: π × radius². A radius of 3 m gives about 28.274 m².
AREA, PERIMETER, AND UNIT CONVERSIONS
Area measures a surface; perimeter measures the distance around its edge. Flooring needs area, while edging usually needs perimeter. One square meter equals 10,000 cm² because both length dimensions are converted. Do not multiply an area by a length-conversion factor just once.
IRREGULAR SPACES AND MATERIAL ESTIMATES
Divide an L-shaped room into two rectangles, calculate each area, and add the results. Subtract openings or cutouts only when they should be excluded from the job. For example, a 20 m² floor with a 2 m² opening has 18 m² of net coverage.
The calculated area does not include cutting waste, overlap, grout spacing, or package sizes. Apply any separate allowance required by the material or installer, then check how much each package covers. Measure carefully and round only at the end; extra displayed decimal places do not make an uncertain measurement more accurate.
Enter dimensions in the same unit, then calculate.