Math.ceil() Method in JS – How to Round Up Numbers

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

Note

• Math.ceil() is one of the built-in methods of the global Math object.
• The global Math object is one of the standard built-in JavaScript objects.

Syntax of the Math.ceil() Method

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

Math.ceil(value);

The value argument represents the number you wish to round up to the nearest integer.

Note

• Suppose the value argument is already an integer. In that case, Math.ceil() will return the same number.
• Math.ceil() is equivalent to -Math.floor(-value).

Examples

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

Round up 9 to the nearest integer

Math.ceil(9);

// The invocation above will return: 9

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AD

Round up 9.999 to the nearest integer

Math.ceil(9.999);

// The invocation above will return: 10

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Round up -9.999 to the nearest integer

Math.ceil(-9.999);

// The invocation above will return: -9

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

Round up 0.91 to the nearest integer

Math.ceil(0.91);

// The invocation above will return: 1

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Round up 0.01 to the nearest integer

Math.ceil(0.01);

// The invocation above will return: 1

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Round up 0 to the nearest integer

Math.ceil(0);

// The invocation above will return: 0

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Tip

• To round down a number, use Math.floor().
• To generate random numbers, use Math.random().