Trapezoid Area Calculator

About this calculator

A trapezoid has exactly one pair of parallel sides, and its area formula averages the length of those two parallel sides before multiplying by the height between them, essentially treating it as a rectangle with an "average" width. This is why the formula works whether the trapezoid is symmetric or leans to one side.

Builders and landscapers reach for this whenever a plot of land, a countertop, or a piece of siding is not a perfect rectangle but has one slanted edge, such as a corner lot or an angled roof section. It is also one of the standard shapes taught in geometry alongside triangles and rectangles, since so many real-world floor plans and land parcels are trapezoidal rather than perfectly rectangular.