Arctan calculator
Find the principal angle whose tan is x. Results are strictly between −90° and 90°, shown in degrees and radians.
Formula
θ = arctan(x); tan(θ) = x; degrees = radians × 180/π.
Angle (radians) ≈ atan((1)) · Angle (degrees) ≈ (0.7853981634)×180÷pi
How to use
- Enter the ratio x.
- Use a finite real value.
- Read the principal angle.
Examples
- arctan(1) = 45°.
Frequently asked questions
What does inverse mean?
It finds an angle from its tan value; it is not 1/tan(x).
Which angle is returned?
The principal angle, strictly between −90° and 90°.
Is the input an angle?
No. x is a unitless tangent ratio.
Sources
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