What is the formula for the area of a trapezoid?

Area = (base_a + base_b) / 2 × height, where base_a and base_b are the two parallel sides and height is the perpendicular distance between them.

Is a trapezoid the same as a trapezium?

In American English, "trapezoid" has exactly one pair of parallel sides; in British English, that shape is called a "trapezium," and the terms are swapped.

Which sides count as the "bases"?

The two parallel sides are the bases. The height must be measured perpendicular to them, not along a slanted side.

Is this tool free to use?

Yes — completely free, no account needed. Everything is calculated entirely in your browser and never uploaded to a server.

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Trapezoid Area Calculator Online

What you can expect

Calculate the area of a trapezoid from its two parallel bases and height with this free online calculator. Uses (a + b) / 2 × height, useful for land plots, roof sections, and geometry homework.

Trapezoid Area

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Frequently asked questions

What is the formula for the area of a trapezoid?: Area = (base_a + base_b) / 2 × height, where base_a and base_b are the two parallel sides and height is the perpendicular distance between them.
Is a trapezoid the same as a trapezium?: In American English, "trapezoid" has exactly one pair of parallel sides; in British English, that shape is called a "trapezium," and the terms are swapped.
Which sides count as the "bases"?: The two parallel sides are the bases. The height must be measured perpendicular to them, not along a slanted side.
Is this tool free to use?: Yes — completely free, no account needed. Everything is calculated entirely in your browser and never uploaded to a server.

For developers

Use Trapezoid Area from Python

Open the Jupyter notebook example to see how to run this tool from the BrushCue Python API, inspect the processing steps, and adapt the workflow for scripts or batch image jobs.

View Python notebook

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