Arctan Calculator

The arctangent function (arctan or tan⁻¹) is the inverse of the tangent function. Given any real number, it returns the angle whose tangent equals that value. The result is always in the range (-90°, 90°) or (-π/2, π/2) radians.

1. Enter any number (positive, negative, or decimal)
2. Select DEG to see result in degrees, or RAD for radians
3. The angle is calculated automatically
4. Both degree and radian values are shown

• Calculate inverse tangent for any real number
• Results in both degrees and radians
• No input restrictions (unlike arcsin/arccos)
• Shows verification: tan(result) = input
• Real-time calculation

Why can arctan accept any number?

Because the tangent function can output any real number (from -∞ to +∞), its inverse can accept any real number as input.

What is arctan(1)?

arctan(1) = 45° or π/4 radians. This means tan(45°) = 1.

What happens as input approaches infinity?

As input → +∞, arctan → 90°. As input → -∞, arctan → -90°. But it never actually reaches ±90°.