The Math.PI property represents the ratio of the circumference of a circle to its diameter, approximately 3.14159:

Math.PI=π3.14159\mathtt{\mi{Math.PI}} = \pi \approx 3.14159

Property attributes of Math.PI
Writable no
Enumerable no
Configurable no


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


Using Math.PI

The following function uses Math.PI to calculate the circumference of a circle with a passed radius.

function calculateCircumference(radius) {
  return Math.PI * (radius + radius);

calculateCircumference(1);  // 6.283185307179586


ECMAScript (ECMA-262)
The definition of 'Math.PI' in that specification.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
PIChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 3Opera Full support 3Safari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support 0.1.100


Full support  
Full support

See also