Example 1
- x = 1
45
What is arctan(1)? 45°. Tangent of one.
Arctan calculator
Type an x, any number. Arctan asks for the angle whose tangent is x. arctan(1) = 45°. arctan(0) = 0°. arctan(√3) comes out 60.000000°.
The result is in degrees. x does not have to sit in [−1, 1]. This is not arcsin. The principal branch runs from −90° to 90°, with no wall at ±1.
Results
Enter data and click Calculate.
How it works
Arctangent undoes tangent. You want an angle θ such that tan θ = x. For x = 1 school writes 45°. The calculator calls Math.atan and multiplies by 180/π. 1 gives a clean 45. √3, typed as 1.7320508075688772, gives 60.000000.
The principal branch is open: from almost −90° to almost 90°. x = 0 gives 0°. A large x climbs toward 90° and never quite reaches it. A minus in x gives a minus angle.
The field is x. There is no ±1 wall here, because tangent takes every real number. 2 passes and gives about 63.434949°. That is not arcsin(2), which on the other card returns 0.
Tangent from an angle is on the neighbouring page. Arcsin needs |x| ≤ 1. Degrees to radians do not invert a tangent.
The header units switch does not multiply anything. 1 stays 45 whatever the label says.
arctan(1) = 45°. arctan(0) = 0°. arctan(√3) = 60.000000°. arctan(−1) = −45°.
Formula
θ° = Math.atan(x) × 180 / π
How to use
- Type x, for example 1.
- Click Calculate. arctan(1) = 45°.
- 0 gives 0°. √3, about 1.73205, gives 60.000000°.
- x may be larger than 1. This is not arcsin.
- Tangent from an angle lives on the tangent card.
arctan(1) = 45°
Arctan undoes tangent. The result is in degrees. arctan(1) = 45°. arctan(0) = 0°. arctan(√3) = 60.000000°.
- arctan
- The angle from a tangent. 1 gives 45°. √3 gives 60.000000°. This is not 1/tan.
- x
- Any number. 0 gives 0°. 2 passes. There is no ±1 wall here.
- Degrees
- The result unit. The calculator multiplies atan by 180/π.
Examples
Example 2
- x = 0
0
What is arctan(0)? 0°. Tangent of zero.
Example 3
- x = 1.7320508075688772
60.000000
What is arctan(√3)? 60.000000°. Type √3 ≈ 1.73205.
Related calculators
Common questions
What is arctan(1)?
45°. tan(45°) = 1, so the return is clean.
What does arctangent mean?
The angle whose tangent is x. Written arctan(x) or tan⁻¹(x), not 1/tan.
What are arctan(0) and arctan(√3)?
0° and 60.000000°. You type √3 as about 1.73205.
Does x have to be from −1 to 1?
No. Tangent takes every number. 2 gives about 63.434949°.
Is the result in radians?
No. The calculator multiplies by 180/π and returns degrees.
How is arctan different from arcsin?
Another function. arcsin(2) on that card returns 0. arctan(2) here passes.
Does a negative x work?
Yes. arctan(−1) = −45°. The minus is the turn.
Does 90° ever come out?
Not on the principal branch. A large x nears 90° and does not reach it.
Where is tangent of 45°?
On the tangent card. Here 1 returns to 45°.
Does a comma in 1.732 work?
Yes. 1.732 and 1,732 are close to √3 and the result is close to 60°.
Knowledge sources
The calculator computes the same formula as the definition below.
Page updated in 2026.