How do you calculate trapezoid area?

Add the two parallel bases, divide by two, and multiply by the perpendicular height.

What is the midsegment of a trapezoid?

The midsegment, or median, connects the midpoints of the legs and has length equal to the average of the two bases.

Can trapezoid area be calculated from diagonals?

Yes, if the angle between the diagonals is known. That input gives area, but it does not determine the bases, height, or perimeter.

Trapezoid Area Calculator

Calculate trapezoid area from bases and height, midsegment and height, four sides, isosceles trapezoid sides, right trapezoid dimensions, or diagonals and angle.

Known values

Unit

The main workflow uses two bases and the perpendicular height. Perimeter is not determined because the legs are unknown.

First base (m)

Second base (m)

Height (m)

Choose the matching mode

Two bases and height: choose the main mode.

Midsegment and height: choose midsegment mode.

All sides are known: use the side compatibility check.

Isosceles trapezoid: enter bases and one leg.

Diagonals and angle: calculate area only.

Trapezoid area from bases, height, or side data

English search intent centers on the classic bases-and-height formula, but competitors often support midsegment, four-side, isosceles, right-trapezoid, and diagonal-angle inputs. This page keeps area first and reports only values determined by the selected input mode.

A = \frac{( a + b ) h}{2}

A is area; a and b are the parallel bases; h is perpendicular height.

m = \frac{a + b}{2}

m is the trapezoid midsegment, also called the median.

A = mh

Area can be calculated from midsegment m and height h.

Supported input modes

Known values	What is returned
Two bases and height	Area and midsegment; perimeter is not determined without legs.
Midsegment and height	Area only, because bases and legs are not recovered.
All four sides	Height, area, perimeter, and side compatibility check.
Isosceles trapezoid bases and leg	Height, area, perimeter, and sketch.
Right trapezoid bases and height	Area, perimeter, and the slanted leg.
Diagonals and included angle	Area only; bases and height are not unique.

Height means the perpendicular distance between the parallel bases. A slanted leg is not the height except in a right trapezoid where one leg is perpendicular to the bases.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

Related Tools

Area Calculator

Calculate area and perimeter for common 2D shapes including rectangle, square, triangle, circle, trapezoid, parallelogram, rhombus, ellipse, annulus, sector, and regular polygon.

Open

Parallelogram Area Calculator

Calculate parallelogram area from base and height, two sides with the included angle, diagonals with their angle, or two sides and one diagonal.

Open

Triangle Area Calculator

Calculate triangle area from base and height, three sides, two sides and an included angle, angles and a side, coordinates, right-triangle legs, or circle radii with three sides.

Open

Rhombus Area Calculator

Calculate rhombus area from diagonals, side and height, side and angle, or side and one diagonal, with perimeter, height, angles, diagonals, and inradius.

Open