Geometry Calculators

Geometry problems usually come down to choosing the right formula and putting the right measurement into it. Most pages here name the formula they use and work an example by hand, so you can check the method as well as the number.

For triangles, the triangle calculator solves a triangle from the sides and angles you know, the right triangle calculator applies the Pythagorean theorem and basic trigonometry, and the triangle area calculator finds the area alone. For circles, the circle calculator finds radius, diameter, circumference and area from any one of them. There are also single-purpose pages for area, circumference, radius and arc length, for when you only need one answer.

For other flat shapes, the polygon calculator handles regular polygons from the number of sides and the side length, and the polygon area calculator finds the area of any polygon from the coordinates of its corners. For solids there are calculators for volume, cones, spheres and cylinder surface area.

Where a page has a unit menu, it only labels the result. It does not convert between units, so put every measurement in the same unit before you start.