Calculators

Trapezoidal Prism Calculator

Calculate right isosceles trapezoidal prism volume, base area, and lateral and total surface areas locally in your browser.

This models a right prism with an isosceles trapezoidal base (equal nonparallel sides). Enter parallel base sides a and b, perpendicular trapezoid height h, and prism length L in the same unit, from 1e-50 to 1e50. Prism length is perpendicular to the trapezoidal ends. Total surface area includes both ends. Equal base sides give a rectangular prism.

Measure a right prism with an isosceles trapezoidal base.

A right isosceles trapezoidal prism has two matching trapezoidal ends with equal nonparallel sides. Enter parallel side lengths a and b, perpendicular trapezoid height h, and prism length L, perpendicular to the end faces. Base area B = (a + b)h/2. Each base leg s = √(h² + ((a − b)/2)²). Base perimeter P = a + b + 2s. Volume = BL, lateral surface area = PL, and total surface area = PL + 2B. For a = 6, b = 4, h = 3 and L = 10, B = 15 square units, volume = 150 cubic units, and total area ≈ 193.245553203 square units. Either parallel side may be larger. Equal parallel sides give a rectangular prism. Surface areas assume an isosceles base and a right prism; these four inputs cannot determine the surface area of an arbitrary trapezoidal or oblique prism. Use one length unit for all dimensions from 1e-50 to 1e50. Scientific notation is accepted; results are rounded to 12 significant digits using browser floating-point arithmetic. All inputs stay in your browser.

Frequently Asked Questions

Everything you need to know about this tool, how it works, and privacy.

Which shapes does this calculator support?

Right prisms with isosceles trapezoidal bases: the nonparallel base sides must be equal, and prism length must be perpendicular to the end faces. Arbitrary trapezoids and oblique prisms need additional measurements for surface area.

Which height and length should I enter?

Trapezoid height h is the perpendicular distance between its parallel sides. Prism length L is the perpendicular distance between the two trapezoidal ends. Use the same length unit for all four dimensions.

How are the results calculated?

Base area B = (a + b)h/2; equal leg s = √(h² + ((a − b)/2)²); perimeter P = a + b + 2s. Volume is BL, lateral area is PL, and total area is PL + 2B.

Can the parallel sides be equal?

Yes. Equal a and b give a rectangular base and a rectangular prism. Either parallel side may be larger. All four dimensions must be positive and from 1e-50 to 1e50.

What is an example?

With parallel sides 6 and 4, trapezoid height 3 and prism length 10, the base area is 15 square units, volume is 150 cubic units, and total surface area is approximately 193.245553203 square units.

Are my measurements uploaded?

No. Calculation, reset, and copying run locally in your browser.