Tangent Calculator

How it works

1. 1Enter your angle and choose degrees or radians using the unit tabs.
2. 2The calculator evaluates tan(θ) = sin(θ) ÷ cos(θ); angles where cosine is 0 (90°, 270°, …) display — rather than a spurious large number.
3. 3The result is rounded to 6 figures; copy it for use in further calculations.

Use cases

• Computing slopes and grades — a 1% grade corresponds to tan(θ) ≈ 0.01.
• Solving right triangles when you know an angle and need the ratio of opposite to adjacent sides.
• Verifying results: tan(45°) = 1, tan(60°) = √3 ≈ 1.732051.

Frequently asked questions

Why does the result show — for 90°?

tan(90°) is undefined because cos(90°) = 0, making sin ÷ cos a division by zero. The calculator displays — instead of ±Infinity.

Which angles give an undefined tangent?

Every odd multiple of 90° — 90°, 270°, 450°, −90°, … (π/2, 3π/2, … radians) — where the cosine equals zero.

What is the range of the tangent function?

Unlike sine and cosine, tangent is unbounded: it spans all real numbers, with vertical asymptotes at every odd multiple of 90°.