Inverse Tangent Calculator (arctan)
Find arctan(x), the angle whose tangent is x, in degrees and radians.
Change the values and press Calculate to work out your own figures.
Enter the value x.
Show the working
- The principal value lies in −90° to 90° (exclusive)
- arctan(1) = 0.7853981634 rad = 45°
How to use it
Enter the value x.
Enter the values you know (decimals, fractions, surds such as 2√5, or angles such as π/3 in radians). Show the working gives the rule used at each step.
Key facts
arctan(x) is the angle in (−90°, 90°) whose tangent is x
Principal value
Many angles share a tangent; the inverse returns the one in the principal range, and the others differ by whole turns (or reflections).
Questions
What is arctan(1)?
45° (π/4).
What values are allowed?
Any number for arctangent; −1 to 1 for arcsine and arccosine.
Formulas
arctan(x) is the angle in (−90°, 90°) whose tangent is x
Sources
Limitations
- Angles can be typed in degrees or radians; radians may be written with π (π/3, 2pi/3).