Triangle Calculator

Solve a triangle's angles and area from its three side lengths.

Side a

Side b

Side c

Angle A44.4°

Angle B57.1°

Angle C78.5°

Area14.70

Ad space — always below the tool, never inside it

How to use triangle calculator

1Enter the three sidesType the length of each side.

2Read the anglesSee all three interior angles, calculated with the law of cosines.

3Check the areaArea is calculated using Heron's formula.

If one side is longer than the sum of the other two, no triangle exists — you'll see a message instead of a result.

The law of cosines for angles, and Heron's formula for area.