This geometry calculator computes the area, perimeter, and angle complements of a trapezoid from its two bases, height, and two non-parallel sides.
Math
Area of a Trapezoid Calculator
Calculate area, perimeter and angles of a trapezoid from sides and height.
Calculator
About this calculator
Formula notes
Area = (baseA + baseB) / 2 x height; Perimeter = baseA + baseB + sideC + sideD; each angle complement = 180 deg minus the adjacent angle.
Worked examples
- Example: bases 5 and 7, height 10, sides 11 and 11, all angles 60 deg gives area 60 and perimeter 34.
- Bases 5 and 7, height 10, sides 11 and 11, all angles 60 deg gives area 60 and perimeter 34.
How to use it
- Enter the two base lengths and the height.
- Enter the two non-parallel side lengths and the four angles.
- Read the area, perimeter, and angle complements.
Frequently asked questions
Why must sides c and d be greater than the height?
In a trapezoid the non-parallel sides must be at least as long as the perpendicular height; otherwise the shape is invalid.
Are the area and perimeter input fields required?
No. Those fields are display-only echoes; the calculator derives area and perimeter from the sides and height.
Limits and interpretation
- The calculator requires sides c and d to be greater than the height h.
- Area and perimeter input fields are display echoes; actual values are derived from the sides and height.