# JavaScript Math floor()

The `Math.floor()` function rounds down a number to the next smallest integer.

### Example

``````let number = 38.8;

// round number to nearest smallest number
let roundedNumber = Math.floor(number);
console.log(roundedNumber);

// Output: 38``````

## Math.floor() Syntax

The syntax of the `Math.floor()` function is:

``Math.floor(x)``

`floor()`, being a static method, is called using the `Math` class name.

## Math.floor() Parameters

The `Math.floor()` function takes in:

• x - A number

## Math.floor() Return Value

• Returns the largest integer less than or equal to a given number.
• Returns 0 for `null`.

## Example: Using Math.floor()

``````// using Math.floor()

var num = Math.floor(1.8645);
console.log(num); // 1

var num = Math.floor(-0.456);
console.log(num); // -1

var num = Math.floor("4");
console.log(num); // 4

// Returns 0 for null
var num = Math.floor(null);
console.log(num); // 0

// Returns NaN for non-numeric types
var num = Math.floor("JavaScript");
console.log(num); // NaN

var num = Math.floor(NaN);
console.log(num); // NaN``````

Output

```1
-1
4
0
NaN
NaN```

Note: `Math.floor()` returns `0` for `null` rather than `NaN`.