Math
Trapezoid Area Calculator
Use the trapezoid area calculator for geometry problems with parallel bases and a perpendicular height.
Area
—
- Average base
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the trapezoid area calculator solves
Use the trapezoid area calculator for geometry problems with parallel bases and a perpendicular height.
Formula
How to use it
- Enter both parallel bases.
- Enter the perpendicular height.
- Multiply the average base by height.
How to read the answer
The formula uses the average of the two parallel bases as the effective width.
Common mistakes and edge cases
- Only the parallel sides are bases.
- Height is perpendicular distance between bases.
- Do not use a slanted leg as height.
Worked examples
Standard trapezoid
Area
32
Nearly rectangle
Area
23.25
Frequently asked questions
Does base order matter?+
No. The bases are added, so base 1 and base 2 can be swapped.
What units does area use?+
Area uses square units matching the input length units.
Why average the bases?+
A trapezoid can be rearranged into a shape whose effective width is the average of the two parallel bases.
Related calculators
Area Calculator
Find the area of rectangles, triangles, circles, trapezoids, and parallelograms with formulas and unit-aware steps.
Triangle Area Calculator
Calculate triangle area from base and height with unit-friendly steps.
Regular Polygon Area Calculator
Calculate regular polygon area from side length and number of sides.
Circle Segment Area Calculator
Calculate circular segment area from radius and central angle, with sector, triangle, and arc-length checks.
Ellipse Area Calculator
Calculate ellipse area from semi-major and semi-minor axes with the pi a b formula and equal-area circle check.
Rectangular Prism Surface Area Calculator
Calculate rectangular prism surface area, face areas, and volume from length, width, and height.
Last updated: May 15, 2026