A parallelogram is a four-sided shape with two pairs of parallel sides. This calculator finds its area, perimeter, and diagonals from whichever measurements you already have — a base and height, or a base, side, and angle — without requiring you to work through the trigonometry by hand.

How the Parallelogram Calculator works

Choose the authoritative input convention in Workflow. In side-angle mode, a is the base, b the adjacent side and θ the included interior angle; h=b sin θ. In height mode, supply the perpendicular height with the labeled base. In inverse-area mode, both supplementary angle branches are reported. Invalid or conflicting supplied geometry clears the result.

Inputs and what they mean

Choose the authoritative input convention in Workflow. In side-angle mode, a is the base, b the adjacent side and θ the included interior angle; h=b sin θ. In height mode, supply the perpendicular height with the labeled base. In inverse-area mode, both supplementary angle branches are reported. Invalid or conflicting supplied geometry clears the result.

Limits and edge cases

Choose the authoritative input convention in Workflow. In side-angle mode, a is the base, b the adjacent side and θ the included interior angle; h=b sin θ. In height mode, supply the perpendicular height with the labeled base. In inverse-area mode, both supplementary angle branches are reported. Invalid or conflicting supplied geometry clears the result.

Use finite values with magnitude at most 1e50. Expressions support pi, sqrt(), fractions and arithmetic. Angles are limited to 1e12 degrees. Units are mathematical; geometry alone does not establish physical safety. Read the linked values, named formulas, diagram coordinate table and any branch or parameter comparison.

Save scenario stores version 2 inputs, workflow, units, precision and selected result on this device. Restore saved scenario replays that snapshot. Share uses the same state; Copy and CSV include the selected answer and all current derived values. Invalid inputs clear the result and disable result exports.