Trapezoid Area Calculator

Where a and b are the lengths of the two parallel sides (bases), and h is the height (perpendicular distance between the bases).

Calculate the area of a trapezoid with bases of 8 cm and 12 cm, and height of 5 cm:

Result: 50 cm²

1. Enter the length of base a
2. Enter the length of base b
3. Enter the height
4. Click "Calculate" to see the area

• Isosceles trapezoid: Non-parallel sides are equal
• Right trapezoid: Has two right angles
• The area formula works for all trapezoids

If height is unknown but all sides are known, divide the trapezoid into a rectangle and two right triangles, then use the Pythagorean theorem.

• Land surveying (irregular plots)
• Roof construction
• Architecture and design
• Engineering
• Graphics and UI design

What if the bases are equal? The trapezoid becomes a parallelogram, and the formula simplifies to base × height.

Can I calculate the perimeter? Yes, add all four sides: P = a + b + c + d.

How do I find the height from the area? $h = \\frac{2 \\times \\text{area}}{a + b}$

Are all parallelograms trapezoids? Yes, under the inclusive definition (at least one pair of parallel sides).

What about the median? The median (midsegment) length is $\\frac{a + b}{2}$, and area = median × height.