Triangle Calculator

Solve a triangle from three side lengths, including angles, perimeter, and area.

Triangle area

Heron's formula

Perimeter12

Semiperimeter6

Angle A36.8699°

Angle B53.1301°

Angle C90°

About the Triangle Calculator

Solve a triangle from three side lengths, including angles, perimeter, and area.

It runs entirely in your browser — nothing you type is sent to a server — and the result updates as you edit the inputs. Estimates are for educational and informational purposes only; see ourdisclaimer.

Common searches

sss triangle
heron
triangle angles

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