What formulas does this calculator use?

Area = 0.5 × (base1 + base2) × height.

What makes a quadrilateral a trapezoid?

It has exactly one pair of parallel sides.

Is a parallelogram a type of trapezoid?

Definitions vary by math tradition on this classification.

Trapezoid Calculator - Area & Perimeter

Trapezoid Calculator

Find the area and perimeter of a trapezoid from its parallel sides and height.

Top Side (a)

Bottom Side (b)

Height (h)

Left / Right Side Lengths (optional, for perimeter)

Area-

Perimeter-

What Is a Trapezoid Calculator?

A trapezoid (also called a trapezium) is a four-sided shape with one pair of parallel sides. This calculator finds its area from the two parallel sides and the height, and its perimeter if you also know the two slanted side lengths.

Formulas

Area: A = ½ × (a + b) × h, where a and b are the parallel (top and bottom) sides and h is the perpendicular height between them.
Perimeter: P = a + b + left side + right side

How to Use This Calculator

Enter the lengths of the top and bottom parallel sides.
Enter the perpendicular height between them.
Optionally enter the two slanted side lengths, separated by a comma, to also get the perimeter.
Click Calculate to see the results.

Worked Example

A trapezoid has a top side of 6 cm, a bottom side of 10 cm, and a height of 4 cm. The area is ½ × (6 + 10) × 4 = 32 cm². If both slanted sides measure 5 cm, the perimeter is 6 + 10 + 5 + 5 = 26 cm.

Common Uses

Trapezoid calculations are useful in architecture (roof and window shapes), land surveying for irregular plots, and cross-sections of channels, ramps, and beams in engineering.