Trapezoid Area Calculator

How the Trapezoid Area Calculator Works

Enter the measurements you have — base lengths, height, midline, diagonals, or an angle — and the area updates immediately. Pick the formula that matches what you know.

A trapezoid is a quadrilateral with exactly one pair of parallel sides, called bases. The other two sides are legs. The height is the perpendicular distance between the bases.

Types of Trapezoids

• Right Trapezoid: One leg forms a 90° angle with the bases. The height equals that leg's length.

• Isosceles Trapezoid: Legs are equal in length. Base angles match. Diagonals are congruent.

• Scalene Trapezoid: All four sides have different lengths. No equal angles or symmetry.

Each type uses the same area formulas — the math does not change with symmetry.

Where You Might Use This

Geometry class: Verify homework answers or check your manual calculations.

Construction: Estimate material for trapezoidal roof sections, land plots, or wall panels.

Landscaping: Calculate the area of irregular garden beds or paved surfaces.

Engineering: Determine cross-sectional areas for trapezoidal channels or beams.

The calculator handles all four formula variants in one place — pick whichever matches your known values.

Area Formulas

Four formulas for calculating trapezoid area, depending on which parameters you have:

Using Bases and Height:

• a and b — lengths of the parallel bases,

• h — height (perpendicular distance between the bases).

Using Midline and Height:

• m — midline length (arithmetic mean of the bases: m = (a + b) / 2),

• h — height.

Using Diagonals and the Angle Between Them:

• d₁ and d₂ — diagonal lengths,

• sin(α) — sine of the angle between the diagonals.