Heron's Formula Calculator
Calculate the area of a triangle from its three side lengths using Heron's formula.
Formula
Area = √(s(s−a)(s−b)(s−c)); s = (a+b+c)/2
- Valid when triangle inequality is satisfied: each side < sum of the other two.
Triangle 5-6-7
Inputs
- Side a: 5
- Side b: 6
- Side c: 7
s=9; Area = √(9×4×3×2) = √216 ≈ 14.70
Frequently asked questions
When is Heron's formula used?
When you know all three sides but no angles or height.