How to Use Math.abs in JavaScript: Absolute Value Explained

Use Math.abs(value) in JavaScript to get the absolute (non-negative) value of a number. It returns the distance of the number from zero, ignoring its sign.

Syntax

The Math.abs() function takes one argument and returns its absolute value.

• value: The number you want to convert to a non-negative value.

javascript

Math.abs(value)

Example

This example shows how Math.abs() converts negative and positive numbers to their absolute values.

javascript

console.log(Math.abs(-10));
console.log(Math.abs(5));
console.log(Math.abs(0));
console.log(Math.abs(-3.14));

Output

10
5
0
3.14

Common Pitfalls

Common mistakes include passing non-numeric values or forgetting that Math.abs() only works with numbers.

Passing undefined, null, or strings that can't convert to numbers will return NaN.

javascript

console.log(Math.abs('text')); // NaN
console.log(Math.abs(undefined)); // NaN

// Correct usage with numeric string:
console.log(Math.abs('-20')); // 20

Output

NaN
NaN
20

Quick Reference

Usage	Description
Math.abs(-5)	Returns 5, the absolute value of -5
Math.abs(0)	Returns 0, absolute value of zero
Math.abs('10')	Returns 10, converts string to number
Math.abs('abc')	Returns NaN, invalid number string

Key Takeaways

Math.abs(value) returns the absolute (non-negative) value of a number.

It works with positive, negative, zero, and numeric strings.

Passing non-numeric or undefined values returns NaN.

Use Math.abs to measure distance or magnitude without sign.

Always ensure the input can convert to a number for correct results.