Triangle area and perimeter calculator

Find the area and perimeter of a triangle from its three sides.

Numbers Stateless

Use a decimal point for fractions and leave out currency and unit symbols.

Quick guide

Try an example

You enter

Side A
3
Side B
4
Side C
5

You get

Area
6
Perimeter
12
How it works & limits

Use positive side lengths in the same unit. The two shorter sides together must be longer than the longest side. Area uses Heron’s formula.

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Circle calculator