Law of Sines Calculator

Calculate unknown sides and angles in any triangle using the Law of Sines

b a c α β γ

Understanding the Law of Sines

What is the Law of Sines?

The Law of Sines states that the ratio of the length of a side of a triangle to the sine of the angle opposite that side is constant for all three sides and angles of a triangle:

a/sin(α) = b/sin(β) = c/sin(γ)

When to Use the Law of Sines

  • When you know two angles and one side (AAS or ASA)
  • When you know two sides and an angle opposite to one of them (SSA)
  • For any triangle - not just right triangles