Trigonometry Calculator

Free online trigonometry calculator. Compute sin, cos, tan, arcsin, arccos, arctan in degrees or radians instantly.

Trigonometric functions relate the angles of a right triangle to the ratios of its sides. This calculator computes sin, cos, and tan for any angle in degrees or radians, and also their inverse functions (arcsin, arccos, arctan) which recover an angle from a known ratio.

Quick Reference Table

  • sin(0°) = 0, sin(30°) = 0.5, sin(45°) ≈ 0.707, sin(60°) ≈ 0.866, sin(90°) = 1
  • cos(0°) = 1, cos(60°) = 0.5, cos(90°) = 0
  • tan(45°) = 1, tan(0°) = 0 — tan is undefined at ±90°
  • Pythagorean identity: sin²θ + cos²θ = 1 (always)

Degrees vs. Radians

Degrees are the everyday unit (360° = full circle). Radians are used in calculus and physics (2π rad = 360°). To convert: multiply degrees by π/180 to get radians, or multiply radians by 180/π to get degrees. Common values: 90° = π/2 ≈ 1.5708 rad, 180° = π ≈ 3.1416 rad.

Trigonometry Basics: Sine, Cosine, and Tangent Explained

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