Math.atan(value) Last updated: 16. May 2026

Returns the arctangent (in radians) of a number. The returned value is between -π/2 and π/2.

See also: Math.tan Math.sin Math.cos

Parameters

Name	Type	Description
value	number	A number representing the tangent of an angle.

Returns

A number between -π/2 and π/2 radians, representing the angle whose tangent is the given value.

Example

Code example (JS)

JS is normal JavaScript either running in the browser or on the Docly™ server.

write(Math.atan(1));
write("\n");
write(Math.atan(0));
write("\n");
/* atan(1) = π/4 ≈ 0.7853981633974483
   atan(0) = 0
   Expected output:
0.7853981633974483
0
*/

Output

The JS code above produces the output shown below:

0.7853981633974483
0