When to use this calculator
Find the area between a trapezoid’s parallel sides. Measure the shortest perpendicular distance between the parallel sides.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Capsule Surface Area Calculator: Find the external area of a cylinder with hemispherical ends.
PUTTING IT INTO PRACTICE
Trapezoid Area: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| First parallel side | 8 |
| Second parallel side | 12 |
| Perpendicular height | 5 |
| Result | 50 square units |
- Check the input labels and enter the example values above.
- Apply the relationship: Area = (a + b) × height ÷ 2.
- The result is 50 square units, rounded for display.
How to interpret your result
Measure the shortest perpendicular distance between the parallel sides.
A perimeter measures the outline; area measures the enclosed surface. Regular polygon tools assume equal sides and angles. For a parallelogram or trapezoid, use the height perpendicular to the selected base.
Frequently asked questions
What does regular polygon mean?
It is a polygon with all sides equal and all interior angles equal.
How do I use the trapezoid area calculator?
Enter first parallel side, second parallel side, perpendicular height. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Area = (a + b) × height ÷ 2.
What should I check before using the result?
Measure the shortest perpendicular distance between the parallel sides.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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