Number

The Number JavaScript object is a wrapper object allowing you to work with numerical values. A Number object is created using the Number() constructor.

Constructor

new Number(value);

Parameters

value
The numeric value of the object being created.

Description

The primary uses for the Number object are:

  • If the argument cannot be converted into a number, it returns NaN.
  • In a non-constructor context (i.e., without the new operator), Number can be used to perform a type conversion.

Properties

Number.EPSILON This is an experimental API that should not be used in production code.
The smallest interval between two representable numbers.
Number.MAX_SAFE_INTEGER This is an experimental API that should not be used in production code.
The maximum safe integer in JavaScript (253 - 1).
Number.MAX_VALUE
The largest positive representable number.
Number.MIN_SAFE_INTEGER This is an experimental API that should not be used in production code.
The minimum safe integer in JavaScript (-(253 - 1)).
Number.MIN_VALUE
The smallest positive representable number - that is, the positive number closest to zero (without actually being zero).
Number.NaN
Special "not a number" value.
Number.NEGATIVE_INFINITY
Special value representing negative infinity; returned on overflow.
Number.POSITIVE_INFINITY
Special value representing infinity; returned on overflow.
Number.prototype
Allows the addition of properties to a Number object.
Properties inherited from Function:

Methods

Number.isNaN() This is an experimental API that should not be used in production code.
Determine whether the passed value is NaN.
Number.isFinite() This is an experimental API that should not be used in production code.
Determine whether the passed value is a finite number.
Number.isInteger() This is an experimental API that should not be used in production code.
Determine whether the passed value is an integer.
Number.isSafeInteger() This is an experimental API that should not be used in production code.
Determine whether the passed value is a safe integer (number between -(253 - 1) and 253 - 1).
Number.toInteger() This is an obsolete API and is no longer guaranteed to work.
Used to evaluate the passed value and convert it to an integer (or Infinity), but has been removed.
Number.parseFloat() This is an experimental API that should not be used in production code.
The value is the same as parseFloat of the global object.
Number.parseInt() This is an experimental API that should not be used in production code.
The value is the same as parseInt of the global object.
Methods inherited from Function:

Number instances

All Number instances inherit from Number.prototype. The prototype object of the Number constructor can be modified to affect all Number instances.

Methods

{{page('/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/prototype', 'Methods')}}

Examples

Example: Using the Number object to assign values to numeric variables

The following example uses the Number object's properties to assign values to several numeric variables:

var biggestNum = Number.MAX_VALUE;
var smallestNum = Number.MIN_VALUE;
var infiniteNum = Number.POSITIVE_INFINITY;
var negInfiniteNum = Number.NEGATIVE_INFINITY;
var notANum = Number.NaN;

Example: Integer range for Number

The following example shows minimum and maximum integer values that can be represented as Number object (for details, refer to EcmaScript standard, chapter 8.5 The Number Type):

var biggestInt = 9007199254740992;
var smallestInt = -9007199254740992;

When parsing data that has been serialized to JSON, integer values falling out of this range can be expected to become corrupted when JSON parser coerces them to Number type. Using String instead is a possible workaround.

Example: Using Number to convert a Date object

The following example converts the Date object to a numerical value using Number as a function:

var d = new Date('December 17, 1995 03:24:00');
print(Number(d));

This displays "819199440000".

Example: Convert numeric strings to numbers

Number("123")     // 123
Number("")        // 0
Number("0x11")    // 17
Number("0b11")    // 3
Number("0o11")    // 9
Number("foo")     // NaN
Number("100a")    // NaN

Specifications

Specification Status Comment
ECMAScript 1st Edition. Standard Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)
The definition of 'Number' in that specification.
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number' in that specification.
Standard New methods and properties added: (EPSILON, isFinite, isInteger, isNaN, parseFloat, parseInt)

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
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