Tangent Calculator

Calculate tangent of any angle. Free online tan calculator for degrees and radians.

The Tangent Calculator computes the tangent value of any angle in degrees or radians. Tangent represents the ratio of sine to cosine, or opposite to adjacent in a right triangle. Essential for slope calculations, angle finding, and many engineering applications. Note that tangent is undefined at 90°, 270°, etc.

Common use cases

  • Slope and gradient calculations
  • Angle of elevation/depression
  • Roof pitch calculations
  • Road grade percentages
  • Ballistics and trajectories

How to use

  1. Enter the angle value
  2. Select degrees or radians
  3. Click calculate for tan(θ)
  4. View the result (undefined at 90°, 270°, etc.)
  5. See the sine/cosine relationship

FAQ

What is tangent?

tan(θ) = sin(θ)/cos(θ) = opposite/adjacent in a right triangle.

What are key tangent values?

tan(0°)=0, tan(30°)≈0.577, tan(45°)=1, tan(60°)≈1.732, tan(90°)=undefined.

Why is tan(90°) undefined?

At 90°, cos(90°)=0, and division by zero is undefined. Tangent approaches ±∞.

How does tangent relate to slope?

Slope = tan(angle). A 45° angle has slope = 1 (rise equals run).