3 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 angle calculators calculators
Angle calculations underpin every geometry topic — and most exam questions reduce to "find the missing angle". The calculators below handle the seven recurring patterns: triangle angle sums (a + b + c = 180°), polygon angle sums ((n − 2) × 180°), complementary (sum 90°) and supplementary (sum 180°) pairs, vertical angles (equal), linear pairs (sum 180°), the four pairs created by a transversal crossing two parallel lines (corresponding, alternate interior, alternate exterior, co-interior), and inscribed-circle angle relationships (inscribed = ½ central). For trig-based angle finding (using arcsin / arccos / arctan), see the Triangle Solver — it handles SSA and SSS cases that reduce to angle problems. Inputs accept degrees, radians, or degrees-minutes-seconds (DMS) format.
This collection has 3 angle calculators: 1 are tagged Most Popular, 1 are supporting tools, and 1 are advanced calculators for derivations and proofs. The most-used tools include Geometry Angle Calculator.