JavaScript Number Reference
JavaScript Numbers
JavaScript has only one type of number.
Numbers can be written with, or without, decimals:
let x = 3.14; // A number with decimals
let y = 34; // A number without decimals
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Large or small numbers can be written with scientific (exponent) notation:
let x = 123e5; // 12300000
let y = 123e-5; // 0.00123
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See Also:
Complete Number Reference
Revised July 2025
| Name | Description |
|---|---|
| constructor | Returns the function that created JavaScript's Number prototype |
| EPSILON | Returns the difference between 1 and the smallest number greater than 1 |
| isFinite() | Checks whether a value is a finite number |
| isInteger() | Checks whether a value is an integer |
| isNaN() | Checks whether a value is Number.NaN |
| isSafeInteger() | Checks whether a value is a safe integer |
| MAX_SAFE_INTEGER | Returns the maximum safe integer in JavaScript. |
| MIN_SAFE_INTEGER | Returns the minimum safe integer in JavaScript |
| MAX_VALUE | Returns the largest number possible in JavaScript |
| MIN_VALUE | Returns the smallest number possible in JavaScript |
| NaN | Represents a "Not-a-Number" value |
| NEGATIVE_INFINITY | Represents negative infinity (returned on overflow) |
| POSITIVE_INFINITY | Represents infinity (returned on overflow) |
| parseFloat() | Parses a string an returns a number |
| parseInt() | Parses a string an returns a whole number |
| prototype | Allows you to add properties and methods to an object |
| toExponential(x) | Converts a number into an exponential notation |
| toFixed(x) | Formats a number with x numbers of digits after the decimal point |
| toLocaleString() | Converts a number into a string, based on the locale settings |
| toPrecision(x) | Formats a number to x length |
| toString() | Converts a number to a string |
| valueOf() | Returns the primitive value of a number |
NOTE
All number methods return a new value.
They do not change the original number.
