Choose a shape, enter its dimensions, and we'll show you step-by-step how to work out the area and perimeter. No sign-up. More: GCSE maths revision · Factorise quadratics · Nth term finder
1. Choose a shape
Square: labels on the diagram match the dimension fields below.
2. Enter dimensions (use the same unit for all, e.g. cm). Leave one blank to find it from area or perimeter.
For area only: triangles and parallelograms need base and perpendicular height; trapeziums need the two parallel sides and perpendicular height. Other sides are only needed for perimeter.
Given (optional): if you want to find a missing dimension, enter area or perimeter here.