Geometry calculators

Area of 11 common 2D shapes — square, rectangle, triangle (base–height & Heron), trapezoid, parallelogram, rhombus, circle, sector, ellipse, regular polygon and annulus — with live diagrams, unit conversions and show/hide steps.

Volume of 13 solids — sphere, cone, cylinder, tank, capsule, cap, frustum, ellipsoid, pyramid, tube, prism, torus.

Total, lateral and base surface area of 13 solids — sphere, cube, cylinder, cone, rectangular tank, capsule, spherical cap, conical frustum, ellipsoid, pyramid, triangular prism, tube (hollow cylinder) and torus — with live diagrams, unit conversions, significant-figures control and full step-by-step working.

Solve any triangle from 3 inputs — SSS, SAS, ASA, AAS and the ambiguous SSA (returns both triangles when they exist). Reports all sides and angles, area (Heron and ½·ab·sinC), perimeter, all three medians, inradius, circumradius, a labeled scale SVG diagram, and show/hide step-by-step working. Degrees or radians.

Solve a² + b² = c² for any missing side, check whether three sides form a right triangle, or find the 3D space diagonal of a box. Live scale diagram, unit selector (mm–km, in/ft/yd), significant-figures control, Pythagorean-triple detector, one-click real-world presets (ladder, screen diagonal, door, ramp) and personalized step-by-step working.

Specialised right-triangle solver: enter any 2 of 7 values — legs a and b, hypotenuse c, either acute angle α or β, altitude h, area A or perimeter P — and get every other value plus the inradius r and circumradius R = c/2. Live to-scale diagram with altitude, degrees/radians toggle, 3-4-5 / 30-60-90 / 45-45-90 presets and step-by-step working.

Specialised isosceles-triangle solver: enter any 2 of 8 values — leg a, base b, either altitude (hb or ha), vertex angle B, base angle A, area K or perimeter P — and get every side, angle, altitude, perimeter, semiperimeter, area, inradius and circumradius R = a²/√(4a²−b²). Live to-scale diagram with axis of symmetry, degrees/radians toggle, equilateral / golden-triangle / 45-45-90 presets, auto-detects equilateral/right/golden cases, and personalised step-by-step working.

Specialised equilateral-triangle solver: enter any one of side a, perimeter P, height h, area A, circumradius R or inradius r — and get every other measurement (all angles are 60°). Live to-scale diagram, unit selector (mm–km, in/ft/yd) with automatic conversion table, presets (yield sign, tetrahedron face, roof gable, reverse-from-area), and personalised step-by-step working.

Know two interior angles of a triangle? Get the third instantly using α + β + γ = 180° (or π radians). Degrees/radians toggle, labelled diagram, step-by-step working, parallel-line and exterior-angle proofs, and worked examples for degree, right-triangle and radian cases.

Solve ASA, AAS and the SSA ambiguous case using a/sin A = b/sin B = c/sin C. Classifies SSA as no / one / two triangles and shows both solutions side-by-side with scaled diagrams, plus every side, angle, area, perimeter, inradius and circumradius, degrees/radians toggle, altitude proof and law-of-sines-vs-cosines comparison.

Distance between two points in 2D and 3D, plus great-circle distance between latitudes/longitudes with the Haversine and Lambert (ellipsoidal) formulas — km and miles, DMS input, click-to-place world map and show/hide step-by-step working.

Slope, distance and angle of incline between two points, or find the second point from one point plus slope/angle and distance. Reports grade %, rise:run ratio, radians and degrees, with a right-triangle diagram and full working.

Solve a circle from any one of radius, diameter, circumference or area, from three points, from a center + point, or from the general equation x² + y² + Dx + Ey + F = 0. Plus arc length, sector, chord, circular segment, annulus, tangent from external point and equivalent-square tools with a live diagram, unit conversions and step-by-step working.