6 free online calculators with step-by-step solutions
Pick the right tool for your problem — 2D shapes, 3D solids, proofs, or composite figures.
Start with these essential parallelogram calculators calculators
A parallelogram is the most general quadrilateral with two pairs of parallel sides — rectangle, rhombus, and square are all special cases. Two facts drive every parallelogram formula: opposite sides and opposite angles are equal, and adjacent angles always sum to 180°. From there, area = base × height (A = b·h) when you know a side and its perpendicular height, A = a·b·sin(θ) when you have two adjacent sides and their included angle, and A = ½·d₁·d₂·sin(α) when you only know the diagonals. The calculators below cover area, perimeter (P = 2(a + b)), diagonals via the parallelogram law (2a² + 2b² = d₁² + d₂²), height, and the four-angle solver from a single known angle.
This collection has 6 parallelogram calculators: 1 are tagged Most Popular, 4 are supporting tools, and 1 are advanced calculators for derivations and proofs. The most-used tools include Parallelogram Angle Solver.