Trapezoid area calculator
Find the area of a trapezoid from its two parallel sides and perpendicular height. Useful for a tapered panel or a geometry exercise. The midline is the average of the parallel sides and gives the equivalent rectangular width.
Free to use. No email or account required.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- Midline length = ( + ) ÷ 2
- Area = Midline length ×
- Worked example
- (8 + 4) ÷ 2 × 3 = 18 m²
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Enter positive metre lengths. Height is the shortest distance between the parallel lines, not a sloping side. Equal bases describe a parallelogram and use the same formula. This tool does not infer the other sides, angles or perimeter.
Sources
- OpenStax — mathematical formulas Sources reviewed: 2026-10-28
Processing and privacy
The calculation or transformation runs in your browser. The tool does not send its input values or generated output to an application server. Loading a page still makes infrastructure requests; optional analytics and Google consent messages have separate controls.
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Sources and maintenance
Maintained by emonster. Sources are listed with their own review dates; these are not live-data timestamps or claims of independent expert certification.
