Triangle Calculator

Calculate triangle area, perimeter, and side angles using Heron's formula.

Enter the three side lengths

💡 Quick Answer & Definition(Verified Formula)

Calculate triangle area, perimeter, and side angles using Heron's formula.

Heron's Formula for Triangle Area

When three sides (a, b, c) are known, area = √[s(s−a)(s−b)(s−c)], where s = (a+b+c)/2 is the semi-perimeter.

Law of Sines and Law of Cosines

Our tool calculates all internal angles and verifies triangle inequality (sum of any two sides must exceed the third).

Types of Triangles

Classifies triangles into Equilateral (all equal sides), Isosceles (two equal sides), Scalene (all unequal), and Right-angled triangles.

100% Free, Instant & Private. All computations run directly in your browser sandbox without sending personal data to any external server.