Calculate the area of rectangles, circles, triangles, trapezoids, parallelograms, and ellipses — with formulas and unit conversion.
| Unit | Area |
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Area measures the amount of two-dimensional space a shape covers, expressed in square units. Every shape has its own formula, but most are built from the same basic ideas: multiplying a base by a height, or using a radius for curved shapes.
A rectangle's area is length times width. A square's area is the side length squared. A circle's area is pi times the radius squared. A triangle's area is half of base times height. A trapezoid's area is half the sum of the two parallel sides, multiplied by the height. A parallelogram's area is base times height, and an ellipse's area is pi times the semi-major axis times the semi-minor axis.
Area scales by the square of the unit conversion factor, not the factor itself. Converting 1 square metre to square feet means multiplying by roughly 10.76, not the linear conversion of about 3.28. This calculator handles that automatically so you can compare results across metric and imperial units.
Area measures the space inside a shape (in square units like m² or ft²), while perimeter measures the total distance around the outside edge (in linear units like m or ft). This calculator shows both wherever applicable.
Measure the length and width of the room in feet, then use the rectangle option (or sum multiple rectangles for irregular rooms) to get the total square footage. Always add 10% extra for cuts and waste when ordering materials.
Not directly — irregular shapes are usually best broken down into a combination of rectangles, triangles, and circles, with each piece calculated separately and the results added together.