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Math.floor() Method in JS – How to Round Down Numbers

Whenever you invoke Math.floor(), the method rounds down its argument to the nearest integer.

Syntax of the Math.floor() Method

Math.floor() accepts only one argument. Here is the syntax:

Math.floor(value);

The value argument represents the number you wish to floor (round down) to the nearest integer.

Examples

Below are examples of the Math.floor() method.

How to round down 9 to the nearest integer

Math.floor(9);
// The invocation above will return: 9

Try it on StackBlitz

How to round down 9.999 to the nearest integer

Math.floor(9.999);
// The invocation above will return: 9

Try it on StackBlitz

How to round down -9.999 to the nearest integer

Math.floor(-9.999);
// The invocation above will return: -10

Try it on StackBlitz

The snippet above returned -10 because -10 is the integer directly below -9.999 on the number line. In other words, -9 is greater than -9.999. But -10 is less than -9.999.

How to round down 0.91 to the nearest integer

Math.floor(0.91);
// The invocation above will return: 0

Try it on StackBlitz