Parallelogram area calculator
Enter the base, the slanted side and the height perpendicular to the base to get the area and the other measurements.
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How to use it
- Enter base, adjacent side, height and length unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Area = base × height, perimeter = 2 × (base + side), acute angle = asin(height ÷ side) and diagonals = √(b² + s² ∓ 2bs × cos θ).
Example
Inputs: Base = 10, Adjacent side = 6, Height = 4, Length unit = Centimeters (cm). Result: Area: 40 cm²; Perimeter: 32 cm; Acute angle: 41.8103 °.
Limits and caveats
- The height must be perpendicular to the base you entered.
- When the height equals the side, the shape is a rectangle and the diagonals are equal.
Questions about this tool
What is the formula for the area of a parallelogram?
Area equals the base times the perpendicular height, not times the slanted side.
Why not multiply the base by the slanted side?
That gives the area of a larger rectangle. A slanted parallelogram has less area than a rectangle with the same sides.
What if I know the angle instead of the height?
The height equals the adjacent side times the sine of the angle; multiply that by the base.