Math
Pythagorean theorem
Find the hypotenuse of a right triangle.
Calculators / Math / Trapezoid / trapezium
Trapezoid / trapezium calculator
Calculate the area and midline of a trapezoid from its parallel sides and perpendicular height.
On this page
Area18square units
Midline length6units
Calculator controls
How to calculate
Calculate the area and midline of a trapezoid from its parallel sides and perpendicular height.
Area = (first parallel side + second parallel side) × perpendicular height ÷ 2; midline = (first parallel side + second parallel side) ÷ 2.
Worked example
First parallel side: 8; Second parallel side: 4; Perpendicular height: 3.
Area: 18 square units; Midline length: 6 units.
Assumptions and limits
The height must be perpendicular to the two parallel sides. “Trapezoid” and “trapezium” naming varies by region.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
A trapezoid has a pair of parallel sides. Its area equals the mean of those side lengths multiplied by their perpendicular separation.
When this tool is useful
Calculate trapezoid area using parallel sides and perpendicular height.
Understanding your inputs
| Input | What to enter |
|---|---|
| First parallel side | Enter a number of at least 0 and no more than 1000000000. |
| Second parallel side | Enter a number of at least 0 and no more than 1000000000. |
| Perpendicular height | Enter a number of at least 0 and no more than 1000000000. |
Frequently asked questions
Can I enter a sloping side as the height?
Only if that side is perpendicular to the bases. Otherwise measure or calculate the perpendicular height first.