geometry calculator

Trapezoid Area Calculator

Calculate trapezoid area for roof sections, channel shapes, land sketches, and classroom geometry where two sides run parallel.

Important Use Notice

Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.

Estimate

Enter job values, review the estimate, then use the decision hints before ordering or quoting.

Estimate Results

Enter values to see the result.

Check

Using the slanted side instead of the perpendicular height
Adding all four sides instead of averaging the two parallel ones

Example

Bases 8 and 12 with height 5 gives area 50

Formula

area = ((baseA + baseB) / 2) x height

Average the two parallel sides first, then multiply by the perpendicular height.

This works well when splitting complex plans into manageable shapes.

Next Step

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FAQ

Which sides count as the bases?

The bases are the two parallel sides of the trapezoid.

Can this help with irregular room sections?

Yes. Trapezoids often appear when a space narrows or widens across a straight span.