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Math

Trapezoid Area Calculator

Calculate area from two parallel bases and their perpendicular separation.

Exact method explained belowEditable inputs

Set up your calculation

Runs on your device

SOLUTION

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter first parallel base, second parallel base, perpendicular height.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Area = (first base + second base) × height ÷ 2. This is the average parallel-base length multiplied by height.

A WORKED EXAMPLE

Parallel bases of 8 and 12 with height 5 give an area of 50 square units.

What to keep in mind

The selected bases must be parallel, and height must be perpendicular to them. Slanted side length is not the height.

Common questions

Can the bases have the same length?

Yes. The formula then reduces to the area of a parallelogram with the supplied base and height.

Does base order matter?

No. Swapping the two base lengths leaves the result unchanged.

Methodology maintained by ClarityKit. How these tools are built and checked.