Isosceles Trapezoid Calculator

The Isosceles Trapezoid Calculator finds the height, area, and perimeter of an isosceles trapezoid from its two parallel sides and its equal legs. Enter the sides.

Formula

h = √(leg² − ((a−b)/2)²); Area = ((a+b)/2)·h; Perimeter = a + b + 2·leg
  • The height comes from the right triangle formed by a leg and the base offset.
  • Both legs are equal in an isosceles trapezoid.

Sides 10, 6, legs 5

Inputs
  • Longer Parallel Side: 10
  • Shorter Parallel Side: 6
  • Leg (equal side): 5

base offset 2, h = √(25−4) = 4.58, area = 8 × 4.58 ≈ 36.7.

Frequently asked questions

How do you find the height of an isosceles trapezoid?
h = √(leg² − ((a−b)/2)²), using the right triangle formed by the leg and the horizontal offset.