Online Tool Store
Trapezium Calculator
Work out the area, perimeter, and missing height of a trapezium from its parallel sides, legs, and any two known measurements.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Math & Science
Trapezium Calculator
Frontend preview — no upload or external service.
Result
a = 8 cm, b = 14 cm, h = 5 cm → area 55 cm², midsegment 11 cm.
How the Trapezium Calculator works
- Enter the two parallel sides — the ones that never meet, however the shape is rotated.
- Add the perpendicular height, or the legs if you need the height solved for you.
- Read the area, midsegment, and perimeter together.
The method
A trapezium's area is the average of its parallel sides multiplied by the perpendicular distance between them, which is the same as treating it as a rectangle of the midsegment's width.
Area = ((a + b) / 2) x h
With a = 8, b = 14 and h = 5: ((8 + 14) / 2) x 5 = 11 x 5 = 55 square centimetres.
FAQ
Is a trapezium the same as a trapezoid?
They are the same shape under different regional names — British English says trapezium for a quadrilateral with one pair of parallel sides, American English says trapezoid. Confusingly, each word means the other shape in the other dialect.
Which measurement is the height?
The perpendicular distance between the parallel sides, not the slanted leg. Using a leg length instead is the single most common error here.
What is the midsegment?
The line joining the midpoints of the two legs. Its length is the average of the parallel sides, which is why it appears directly in the area formula.
How we compare
| Feature | Online Tool Store | A graphing calculator | A stats package |
|---|---|---|---|
| Midsegment shown | ✓ | ✗ | Sometimes |
| Solves for a missing height | ✓ | ✗ | ✓ |
| Formula explained on the page | ✓ | ✗ | ✗ |
| No sign-up | ✓ | ✓ | Varies |
Trapezium Calculator shows the working, not just the number, because the mistake is nearly always using a slanted leg where the perpendicular height belongs.