# Using The Math.ceil() Function In Javascript To Round a Number Up

### Introduction

To round a number up in Javascript, you can use the `Math.ceil()`

function.

This function accepts a `number`

as an argument, rounds it up, and then returns that number.

## Using Math.ceil()

You can write a function to take a number and return the smallest integer greater than or equal to the input:

`function ceilNumber(num) { let ceil = Math.ceil(num); console.log(ceil); }`

This function applies the `Math.ceil()`

and logs the result.

You can see this in action below:

`ceilNumber(5); // 5 ceilNumber(5.001); // 6 ceilNumber(5.999); // 6`

## Math.ceil() vs Math.floor()

The `Math.floor()`

function, unlike the `Math.ceil()`

method, round the number **down**.

`console.log(Math.ceil(5.999)); // 6 console.log(Math.floor(5.999)); // 5`

You can learn more about it on Math.floor() Function in Javascript, Uses, Limitations, Type Coercion.