Triangle Calculator

Solve any triangle using sides and angles. Calculate area, perimeter, heights, and identify triangle types (SSS, SAS, ASA, AAS).

Result

Fill in the fields above, then press Calculate.

A triangle calculator solves any triangle given a combination of sides and angles (SSS, SAS, ASA, AAS), computing all missing measurements, area, and perimeter using the Law of Sines and Law of Cosines.

Enter the sides and angles you know (e.g. two sides and one angle, or three sides). The calculator uses the Law of Sines and Law of Cosines to find the missing sides, angles, area, and perimeter. Select the layout that matches your given information, fill in the values, and click Calculate.

Examples

Right Triangle (3-4-5)

Sides a = 3, b = 4, c = 5. Angles: 36.87°, 53.13°, 90°. Area = 6 square units. Perimeter = 12.

SAS Triangle

Sides a = 8, b = 6, included angle C = 60°. Side c ≈ 7.21, Area ≈ 20.78 square units using the formula ½ab sin(C).

Frequently Asked Questions

What is the sum of angles in a triangle?
The sum of internal angles in any Euclidean triangle is always exactly 180 degrees.

Key Terms

SSS
Side-Side-Side
SAS
Side-Angle-Side
ASA
Angle-Side-Angle
Related Calculators
Right Triangle Calculator
Pythagorean Theorem Calculator
Area Calculator
Distance Calculator

Quick Tips

  • •Double-check your inputs — small errors in angles or sides lead to large errors in the solved triangle.
  • •Use the step-by-step breakdown to verify intermediate calculations.
  • •When given a choice, prefer the SAS or SSS method over ASA/AAS to minimize cumulative rounding.