Trapezoid Area Calculator
Find a trapezoid's area, median and perimeter in one step — enter the two parallel sides and the height for area, or add the two legs to get the perimeter. Formulas are shown so you can follow the working.
How to use
- Enter the parallel sides a and b and the height.
- Also enter legs c and d to get the perimeter.
- The median (average of the two parallel sides) also shows in the result.
Note: Formula: Area = ((a + b) / 2) x height. Median = (a + b) / 2, and Area can also be written as median x height. Perimeter is the sum of all four sides.
Good to know
- Area = ((a + b) / 2) × height — the median times the height gives the same result.
- Sides a and b must be the parallel pair; the legs c and d are only needed for the perimeter.
- All four sides must use the same unit, or the answer will be wrong.
Frequently Asked Questions (FAQ)
What inputs does the trapezoid area calculator need?
The two parallel sides (a and b) and the height for the area and median. Add the two legs (c and d) if you also want the perimeter.
What formula does it use?
Area equals (a + b) divided by 2 times the height, which is the same as the median times the height.
Are the legs needed for the area?
No. The legs c and d are only needed for the perimeter; sides a and b must be the parallel pair.
Do all measurements need the same unit?
Yes. All four sides must use the same unit, or the answer will be wrong.