**Javascript round number**

In this article, we will understand how to round a decimal to its nearest integer in javascript using its `Math.round()`

function with examples.

**Math.round()**

Javascript

`Math`

object has a `round()`

function which accepts a decimal number as argument and rounds it off to the nearest integer as per the following rules.- If the
**first digit after decimal**is*greater than or equal to*5, then the number is rounded off to the next integer.

So, 6.5, 6.532, 6.683 etc., are rounded to 7. - If the
**first digit after decimal**is*lesser than*5, then the number is rounded off to the previous integer.

So, 6.4, 6.489, 6.199 etc., are rounded to 6. - Same rules apply for negative numbers
**except**for the case when the**first digit after decimal**is**exactly**0.5.

In this situation, the number is rounded off to the previous integer as opposed to next integer as for positive numbers.

So, -2.3, -5.4, -1.2 will be rounded off to -2, -5 and -1 respectively.

-2.6, -5.7, -1.8 will be rounded off to -3, -6 and -2 respectively, and

-8.5, -23.5, -45.5 will be rounded to -8, -23 and -45(**Note this**).

**Syntax**

`round()`

is a static method of `Math`

object and so, you don’t need **create a javascript object** to call it.

Following is the syntax of `round()`

function

Math.round(number)

where, number is the decimal value to be rounded.

**Examples**

Below are some of the examples of

`Math.round()`

let num1 = Math.round(89.5) console.log(num1); let num2 = Math.round(33.2) console.log(num2); let num3 = Math.round(21.2999) console.log(num3); console.log('--- Rounding negative numbers ---); let num4 = Math.round(-12.7) console.log(num4); let num5 = Math.round(-2.05) console.log(num5); // notice this let num6 = Math.round(-54.5) console.log(num6);

This is the output

90

33

21

— Rounding negative numbers —

-13

-2

-54

**Passing string argument**

`round()`

function may be provided a string as an argument. It will return the same result if the string is parseable or convertible to a number, such as ’34’, ‘67.4’ etc.

If the string is not convertible to numeric format, then `round()`

will return `NaN`

. **Example,**

console.log(Math.round('23.4')); console.log(Math.round('-12.5')); console.log(Math.round('one'));

Output will be

23

-12

NaN

**Browser support**

`round()`

function is supported by all the browsers. Following is a table of `round()`

compatibility with different browser versions.

Browser | Version |
---|---|

Chrome | 1 |

Firefox | 1 |

IE | 3 |

Edge | 12 |

Safari | 1 |

Opera | 3 |