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Geometry

Trapezoid Area Calculator

Average the parallel side lengths and multiply by the height.

Let’s calculate.

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Your result
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Rounded to up to 2 decimal places.

Measurement units

Changing the input unit also selects its matching result unit. Choose another result unit to convert the answer. Input numbers stay unchanged.

SI prefixes and selected international / customary units. Coverage: SI and selected current customary units. Historical units are excluded.

See what you’re calculating

hbase / width
Area = (a + b) × height / 2

Average the parallel side lengths and multiply by the height.

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THE IDEA, SIMPLY

How it works

Average the parallel side lengths and multiply by the height.

FORMULA

Area = (a + b) × height / 2

A worked example

Parallel sides 8 m and 4 m, height 3 m: 18 m².

Formula & detailed explanation

All lengths nonnegative. Sides a and b must be parallel.

Calculations use decimal arithmetic with 40 significant digits internally. Choose 0–8 decimal places for the displayed result. Trailing zeros are omitted. Rounding affects only the displayed and copied result; very small values may round to zero. Accepted inputs have up to 100 characters and magnitudes from 10⁻¹⁰⁰ to 10¹⁰⁰, plus zero.

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