The Number
constructor contains constants and methods for working with numbers. Values of other types can be converted to numbers using the Number()
function.
The JavaScript Number type is a double-precision 64-bit binary format IEEE 754 value, like double
in Java or C#. This means it can represent fractional values, but there are some limits to what it can store. A Number only keeps about 17 decimal places of precision; arithmetic is subject to rounding. The largest value a Number can hold is about 1.8×10308. Numbers beyond that are replaced with the special Number constant Infinity
.
A number literal like 37
in JavaScript code is a floating-point value, not an integer. There is no separate integer type in common everyday use. (JavaScript now has a BigInt
type, but it was not designed to replace Number for everyday uses. 37
is still a Number, not a BigInt.)
Number may also be expressed in literal forms like 0b101
, 0o13
, 0x0A
. Learn more on numeric lexical grammar here.
Description
When used as a function, Number(value)
converts a string or other value to the Number type. If the value can't be converted, it returns NaN
.
Literal syntax
123 // one-hundred twenty-three 123.0 // same 123 === 123.0 // true
Function syntax
Number('123') // returns the number 123 Number('123') === 123 // true Number("unicorn") // NaN Number(undefined) // NaN
Constructor
Number()
- Creates a new
Number
value.
Static properties
Number.EPSILON
- The smallest interval between two representable numbers.
Number.MAX_SAFE_INTEGER
- The maximum safe integer in JavaScript (
253 - 1
). Number.MAX_VALUE
- The largest positive representable number.
Number.MIN_SAFE_INTEGER
- 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 the
Number
object.
Static methods
Number.isNaN()
- Determine whether the passed value is
NaN
. Number.isFinite()
- Determine whether the passed value is a finite number.
Number.isInteger()
- Determine whether the passed value is an integer.
Number.isSafeInteger()
- Determine whether the passed value is a safe integer (number between
-(253 - 1)
and253 - 1
). Number.parseFloat(string)
- This is the same as the global
parseFloat()
function. Number.parseInt(string, [radix])
- This is the same as the global
parseInt()
function.
Instance methods
Number.prototype.toExponential(fractionDigits)
- Returns a string representing the number in exponential notation.
Number.prototype.toFixed(digits)
- Returns a string representing the number in fixed-point notation.
Number.prototype.toLocaleString([locales [, options]])
- Returns a string with a language sensitive representation of this number. Overrides the
Object.prototype.toLocaleString()
method. Number.prototype.toPrecision(precision)
- Returns a string representing the number to a specified precision in fixed-point or exponential notation.
Number.prototype.toString([radix])
- Returns a string representing the specified object in the specified radix ("base"). Overrides the
Object.prototype.toString()
method. Number.prototype.valueOf()
- Returns the primitive value of the specified object. Overrides the
Object.prototype.valueOf()
method.
Examples
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:
const biggestNum = Number.MAX_VALUE const smallestNum = Number.MIN_VALUE const infiniteNum = Number.POSITIVE_INFINITY const negInfiniteNum = Number.NEGATIVE_INFINITY const notANum = Number.NaN
Integer range for Number
The following example shows the minimum and maximum integer values that can be represented as Number
object. (More details on this are described in the ECMAScript standard, chapter 6.1.6 The Number Type.)
const biggestInt = Number.MAX_SAFE_INTEGER // (253 - 1
) => 9007199254740991 const smallestInt = Number.MIN_SAFE_INTEGER // -(253 - 1
) => -9007199254740991
When parsing data that has been serialized to JSON, integer values falling outside of this range can be expected to become corrupted when JSON parser coerces them to Number
type.
A possible workaround is to use String
instead.
Larger numbers can be represented using the BigInt
type.
Using Number to convert a Date object
The following example converts the Date
object to a numerical value using Number
as a function:
let d = new Date('December 17, 1995 03:24:00') console.log(Number(d))
This logs 819199440000
.
Convert numeric strings and null to numbers
Number('123') // 123 Number('123') === 123 /// true Number('12.3') // 12.3 Number('12.00') // 12 Number('123e-1') // 12.3 Number('') // 0 Number(null) // 0 Number('0x11') // 17 Number('0b11') // 3 Number('0o11') // 9 Number('foo') // NaN Number('100a') // NaN Number('-Infinity') //-Infinity
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Number' in that specification. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Number | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
EPSILON | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 25 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 25 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
MAX_SAFE_INTEGER | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 31 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 31 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
MAX_VALUE | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
MIN_SAFE_INTEGER | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 31 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 31 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
MIN_VALUE | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
NaN | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
NEGATIVE_INFINITY | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Number() constructor | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
POSITIVE_INFINITY | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
isFinite | Chrome Full support 19 | Edge Full support 12 | Firefox Full support 16 | IE No support No | Opera Full support 15 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 25 | Firefox Android Full support 16 | Opera Android Full support 14 | Safari iOS Full support 9 | Samsung Internet Android Full support 1.5 | nodejs Full support 0.10 |
isInteger | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 16 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 16 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
isNaN | Chrome Full support 25 | Edge Full support 12 | Firefox Full support 15 | IE No support No | Opera Full support 15 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 25 | Firefox Android Full support 15 | Opera Android Full support 14 | Safari iOS Full support 9 | Samsung Internet Android Full support 1.5 | nodejs Full support 0.10 |
isSafeInteger | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 32 | IE No support No | Opera Full support 21 | Safari Full support 10 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 32 | Opera Android Full support 21 | Safari iOS Full support 10 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
parseFloat | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 25 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 25 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
parseInt | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 25 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 25 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
toExponential | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 5.5 | Opera Full support 7 | Safari Full support 2 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
toFixed | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 5.5 | Opera Full support 7 | Safari Full support 2 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
toLocaleString | Chrome Full support 1 | Edge
Full support
12
| Firefox Full support 1 | IE
Full support
5
| Opera Full support 4 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
toPrecision | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 5.5 | Opera Full support 7 | Safari Full support 2 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
toSource | Chrome No support No | Edge No support No | Firefox
No support
1 — 74
| IE No support No | Opera No support No | Safari No support No | WebView Android No support No | Chrome Android No support No | Firefox Android Full support 4 | Opera Android No support No | Safari iOS No support No | Samsung Internet Android No support No | nodejs No support No |
toString | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 4 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
valueOf | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 4 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Legend
- Full support
- Full support
- No support
- No support
- Non-standard. Expect poor cross-browser support.
- Non-standard. Expect poor cross-browser support.
- See implementation notes.
- See implementation notes.
See also
NaN
Arithmetic operators
- The
Math
global object - Integers with arbitrary precision:
BigInt