Math.atanh()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It's been available across browsers since July 2015.

The Math.atanh() static method returns the inverse hyperbolic tangent of a number. That is,

\begin{aligned}\forall x \in ({-1}, 1),\;\mathtt{\operatorname{Math.atanh}(x)} &= \operatorname{artanh}(x) = \text{the unique } y \text{ such that } \tanh(y) = x \\&= \frac{1}{2}\,\ln\left(\frac{1+x}{1-x}\right)\end{aligned}

Try it

console.log(Math.atanh(-1));
// Expected output: -Infinity

console.log(Math.atanh(0));
// Expected output: 0

console.log(Math.atanh(0.5));
// Expected output: 0.549306144334055 (approximately)

console.log(Math.atanh(1));
// Expected output: Infinity

Syntax

Math.atanh(x)

Parameters

x: A number between -1 and 1, inclusive.

Return value

The inverse hyperbolic tangent of x. If x is 1, returns Infinity. If x is -1, returns -Infinity. If x is less than -1 or greater than 1, returns NaN.

Description

Because atanh() is a static method of Math, you always use it as Math.atanh(), rather than as a method of a Math object you created (Math is not a constructor).

Examples

Using Math.atanh()

Math.atanh(-2); // NaN
Math.atanh(-1); // -Infinity
Math.atanh(-0); // -0
Math.atanh(0); // 0
Math.atanh(0.5); // 0.5493061443340548
Math.atanh(1); // Infinity
Math.atanh(2); // NaN

Specifications

Specification
ECMAScript® 2027 Language Specification # sec-math.atanh

Browser compatibility

	Desktop					Mobile							Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`atanh`	38	12	25	25	8	38	25	25	8	3.0	38	8	1.0.0	1.0	0.12.0