Trapezium area calculator
Enter both parallel sides and the height of the trapezium, and the calculator works out the area with the numbers substituted into the formula.
A trapezium with parallel sides 10 and 6 and height 4 has an area of 32.00.
Formula
a and b are the two parallel sides and h the height between them. Their sum halved is their average.
How we got there
The formula reads as “the average of the parallel sides times the height” — the same as a rectangle whose side is that average.
How to work out the area of a trapezium by hand
- Add the two parallel sides
10 + 6 = 16.
- Multiply the total by the height
16 × 4 = 64.
- Halve it
64 ÷ 2 = 32. That is the area of the trapezium.
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Frequently asked questions
Add the parallel sides, multiply by the height and divide by two: ((10 + 6) × 4) ÷ 2 = 32.
The two that run parallel to each other. The other two are the legs.
The distance between the parallel sides measured at a right angle, not the length of a leg.
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