Trapezoid Calculator
Area from the two bases and the height, with the midsegment.
Work out Trapezoid. Area from the two bases and the height, with the midsegment. Exact formulas, checked against worked examples.
The other parallel side.
Perpendicular distance between the bases.
Optional — for the perimeter.
Optional — for the perimeter.
Area (units²)
32
Midsegment 8 units
Area is the average of the two parallel sides times the height. That average is the midsegment — 8 here — so a trapezoid has exactly the area of a rectangle that wide and that tall. Seeing it that way makes the formula obvious rather than something to memorise.
How the Trapezoid Calculator works
A trapezoid's area is the average of its two parallel sides times the height. That average is also the midsegment, which means a trapezoid has exactly the area of a rectangle as wide as its midsegment — a way of seeing the formula that makes it obvious rather than something to memorise.
Also known as: area of a trapezoid · trapezium area calculator · trapezoid area formula · area of a trapezium
Frequently asked questions
How do I find the area of a trapezoid?
Add the two parallel sides, halve the result, and multiply by the height. Bases of 10 and 6 with a height of 4 give 8 × 4 = 32 square units.
What is the midsegment?
The line halfway up, parallel to both bases. Its length is the average of the two bases — 8 in the example above — and it is why the area formula works.
Is a trapezoid the same as a trapezium?
In British usage a trapezium is what Americans call a trapezoid: a quadrilateral with one pair of parallel sides. The words are swapped between the two conventions, which is a genuine and long-standing source of confusion.
Which height should I use?
The perpendicular distance between the parallel sides, not the length of a sloping side. Using a slanted side overstates the area.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/trapezoid-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Trapezoid Calculator"></iframe>The only condition is that the credit line stays visible. It sits inside the frame, so you do not have to do anything to keep it.
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