This is a new technology, part of the ECMAScript 2015 (ES6) standard .
This technology's specification has been finalized, but check the compatibility table for usage and implementation status in various browsers.

The Math.sign() function returns the sign of a number, indicating whether the number is positive, negative or zero.




A number.


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

This function has 5 kinds of return values, 1, -1, 0, -0, NaN, which represent "positive number", "negative number", "positive zero", "negative zero" and NaN respectively.

The argument passed to this function will be converted to x type implicitly.


Using Math.sign()

Math.sign(3);     //  1
Math.sign(-3);    // -1
Math.sign('-3');  // -1
Math.sign(0);     //  0
Math.sign(-0);    // -0
Math.sign(NaN);   // NaN
Math.sign('foo'); // NaN
Math.sign();      // NaN


Math.sign = Math.sign || function(x) {
  x = +x; // convert to a number
  if (x === 0 || isNaN(x)) {
    return x;
  return x > 0 ? 1 : -1;


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.sign' in that specification.
Standard Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 38 25 (25) Not supported 25 Not supported
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported Not supported 25.0 (25) Not supported Not supported Not supported

See also

Document Tags and Contributors

Last updated by: fscholz,