Find the area, midsegment, and perimeter of a trapezoid. Enter the two parallel sides, the height, and the legs.
Usage Tip
The midsegment of a trapezoid is exactly the average of the two parallel sides — and the area is the midsegment times the height.
midsegment = (a + b) ÷ 2
The midsegment connects the midpoints of the legs and equals that average.
The legs are used only for the perimeter.
Enter all five lengths in the same units.
A trapezoid has one pair of parallel sides, called the bases. Its area equals the average of the two bases multiplied by the height, which is the perpendicular distance between them. The midsegment is the line joining the midpoints of the two legs, and its length is the average of the two bases.
The height is not the same as the length of a slanted leg, which is a common mistake. Measure it at a right angle to the bases. The perimeter simply adds all four sides, so the calculator needs the leg lengths for that value. Trapezoid areas appear in land measurements, roof and ramp layouts, and cross sections of channels.