Trapezoid Area Calculator
Enter the two parallel sides and the height of a trapezoid to find its area.
units
units
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6.5
Formula
Examples
| Input | Result |
|---|---|
| a = 8, b = 5, height = 4 | Area = 26, Midline = 6.5 |
About this calculator
A trapezoid (called a trapezium in British English) is a quadrilateral with exactly one pair of parallel sides, known as the bases. Its area equals the average of the two parallel sides multiplied by the perpendicular distance between them.
The midline, or median, is the segment connecting the midpoints of the non-parallel sides; its length is the average of the two bases, which is why the area can also be read as midline × height. This shape is common in roof cross-sections, embankments and land plots.
Frequently asked questions
Area = ½ × (a + b) × h, where a and b are the parallel sides and h is the perpendicular height between them.
A trapezoid has exactly one pair of parallel sides — these are the bases (a and b). The height is the perpendicular gap between them, not the slanted sides.
The midline is the average of the two parallel sides, (a + b) / 2. Multiplying it by the height also gives the area.
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