7 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 quadrilateral calculators calculators
A quadrilateral is any four-sided polygon — square, rectangle, parallelogram, rhombus, trapezoid, kite, or fully irregular. They share one universal property (interior-angle sum = 360°) and otherwise diverge: some have parallel sides, some don't; some have equal diagonals, others have perpendicular ones. The calculators below let you compute area, perimeter, diagonals, angles, and vertex coordinates for each named quadrilateral family, plus a generic "any 4 vertices" solver that uses the Shoelace formula for irregular shapes. If your shape fits a named family (e.g. a rectangle), use the dedicated tool — it asks for fewer inputs and shows the family-specific formulas (P = 2(l + w), d = √(l² + w²) for rectangles).
This collection has 7 quadrilateral calculators: 3 are tagged Most Popular, 4 are supporting tools. The most-used tools include Quadrilateral Angle Calculator, Quadrilateral Shape Calculator, Parallelogram Congruence Calculator.