How to calculate area
- Choose a shape: rectangle, square, circle, triangle, trapezoid, parallelogram, ellipse, rhombus, sector, ring or regular polygon.
- Enter the measurements shown in the diagram and choose the unit you measured in.
- Read the area in your unit, the formula used, and conversions to square metres, square feet, acres, hectares and more.
Area formulas at a glance
Area measures the flat surface inside a shape, in square units. Rectangles use length × width, triangles half of base × height (the height is measured at right angles to the base, not along a slanted side), circles π × radius², and trapezoids the average of the two parallel sides × height. Ellipses generalise the circle as π × a × b, a rhombus is half the product of its diagonals, and a regular polygon with n equal sides of length s has area n·s² ÷ (4·tan(π/n)), so a hexagon with 2 m sides covers about 10.39 m².
Real-world uses include flooring, turf, paint and fertiliser estimates, land and room sizes, fabric, solar panels and homework checks. For irregular rooms, split the floor plan into rectangles and triangles, calculate each, and add them up. Area conversions are exact: 1 ft² = 0.09290304 m², 1 acre = 4,046.86 m², and 1 hectare = 10,000 m². Everything is calculated in your browser.
How do I find the area of an L-shaped room?
Split it into two rectangles, calculate each area and add them together.
How many square feet are in a square metre?
About 10.764 square feet.
How do I calculate the area of a circle from its diameter?
Halve the diameter to get the radius, then use πr².