Reviewed by CalcMulti Editorial Team·Last updated: ·← Geometry Hub
The perimeter of a shape is the total length of its boundary — the distance you'd walk if you went all the way around the outside edge. For a rectangle it's 2(l+w), for a circle it's 2πr (called circumference), for a triangle it's a+b+c.
Perimeter is measured in length units (cm, m, ft, in) unlike area which uses square units. It's used in fencing calculations, framing projects, track distances, and any situation where you need to know how much material goes around the outside.
This calculator covers the most common shapes: rectangle, square, triangle, circle, parallelogram, and regular pentagon. Select the shape and enter its dimensions.
Rectangle: P = 2(l + w)
½bh — all triangle types and methods
Circle Area CalculatorA = πr² — area and circumference
Rectangle AreaArea of rectangles and regular polygons
Polygon Area CalculatorRegular polygons with 3–12 sides
Right Triangle CalculatorFind all sides and angles of a right triangle
Surface Area Calculator3D shapes — cube, cylinder, sphere, cone
This calculator is for educational purposes only and does not constitute professional advice. Results are based on standard mathematical formulas. Always verify critical calculations with a qualified professional before making important decisions.