Math.PI
The Math.PI
property represents the ratio of the circumference of a circle to its diameter, approximately 3.14159:
$$\backslash mathtt\{\backslash mi\{Math.PI\}\}\; =\; \backslash pi\; \backslash approx\; 3.14159$$
Property attributes of Math.PI 


Writable  no 
Enumerable  no 
Configurable  no 
Description
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).
Examples
Using Math.PI
The following function uses Math.PI
to calculate the circumference of a circle with a passed radius.
function calculateCircumference(radius) { return 2 * Math.PI * radius; } calculateCircumference(1); // 6.283185307179586
Specifications
Specification  Status  Comment 

ECMAScript 1st Edition (ECMA262)  Standard  Initial definition. Implemented in JavaScript 1.0. 
ECMAScript 5.1 (ECMA262) The definition of 'Math.PI' in that specification. 
Standard  
ECMAScript 2015 (6th Edition, ECMA262) The definition of 'Math.PI' in that specification. 
Standard  
ECMAScript 2017 Draft (ECMA262) The definition of 'Math.PI' in that specification. 
Draft 
Browser compatibility
Feature  Chrome  Firefox (Gecko)  Internet Explorer  Opera  Safari 

Basic support  (Yes)  (Yes)  (Yes)  (Yes)  (Yes) 
Feature  Android  Chrome for Android  Firefox Mobile (Gecko)  IE Mobile  Opera Mobile  Safari Mobile 

Basic support  (Yes)  (Yes)  (Yes)  (Yes)  (Yes)  (Yes) 
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons AttributionShareAlike License v2.5 or later.
https://developer.mozilla.org/enus/docs/web/javascript/reference/global_objects/math/pi