Heron's Formula Calculator

Find a triangle's area from its three sides.

Area 14.697

Perimeter 18

Formula: s = (a+b+c)/2 ; area = √(s(s−a)(s−b)(s−c))

Step-by-step with your numbers:

1. Values used:

2. Side a = 5

3. Side b = 6

4. Side c = 7

6. Area = 14.697

7. Perimeter = 18

Did we solve your problem today?

Find a triangle's area knowing only its three side lengths.

The math behind it

Semi-perimeter s = (a+b+c)/2; area = √(s(s−a)(s−b)(s−c)).

5, 6, 7 → area 14.70.

Invalid triangle?

If any side ≥ the sum of the others, no triangle exists (area is 0).