In this article, you’ll learn how to **convert a negative number to a positive in JavaScript** by multiplying it by `-1`

or using the functions of the Math class. Let’s see the specific steps to do it below.

## Convert a negative number to a positive in JavaScript

### Multiplying the number by -1

There are many ways you can do that, all of them practically the same.

Using * (Multiply), it’s the same as how you’d do in Math:

**Code:**

const x = -5; const y = x * -1; console.log(y);

**Output:**

`5`

Using `-`

(Negative, not minus), you can consider it the shorthand version of `(x * -1)`

. It’s exactly the same as how you’d do in Math:

**Code:**

const x = -5; const y = -x; console.log(y);

**Output:**

`5`

While this works fine **if you know for sure the value is negative**; otherwise, you might accidentally make it negative.

To deal with this, it’s required you use the `Math`

class.

The `Math`

class is a class that provides mathematical methods and constants (i.e. `PI`

).

### Using `Math.prototype.sign()`

The `Math`

class’ `.sign()`

function takes a number and returns its sign, but returns `0`

if the number is zero.

So technically, if you take a number and multiply it by its sign, you’ll always get a positive number like the following code:

**Code:**

const neg = -5; const pos = 5; const zero = 0; function signPostive(num) { console.log(num * Math.sign(num)); } console.log(signPostive(neg)); // -5 * -1 console.log(signPostive(pos)); // 5 * 1 console.log(signPostive(zero)); // 0 * 0

**Output:**

```
5
5
0
```

Additionally, the `.sign()`

function has more utility in deciding whether a number is `false`

.

**Code:**

const neg = -5; const pos = 5; const zero = 0; function signPostive(num) { if (Math.sign(num) === -1) { console.log(-num); } else { console.log("Is not a negative number"); } } console.log(signPostive(neg)); console.log(signPostive(pos)); console.log(signPostive(zero));

**Output:**

```
5
"Is not a negative number"
"Is not a negative number"
```

However, this seems a little redundant, so instead, it would be better to use the `Math`

class’ `.abs()`

function.

**Using **`Math.prototype.abs()`

`Math.prototype.abs()`

The `Math`

class’ `.abs()`

function takes a number and returns a positive number. It’s a stand-in for the absolute value sign, as such:

**Code:**

const neg = -5; const pos = 5; const zero = 0; // Using the Math.prototype.abs() function, convert a negative number to a positive console.log(Math.abs(neg)); console.log(Math.abs(pos)); console.log(Math.abs(zero));

**Output:**

```
5
5
0
```

**Summary**

To **convert a negative number to a positive number in JavaScript**, you need to either multiply the number by `-1`

or multiply that number with its sign using the `Math`

class’ `.sign()`

function or just use the Math class’ `.abs()`

function. You can find documentation on the `Math`

class’ other properties and methods here.

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Hello, my name is Davis Cole. I love learning and sharing knowledge about programming languages. Some of my strengths are Java, HTML, CSS, JavaScript, C#,… I believe my articles about them will help you a lot.

**Programming Languages**: Java, HTML, CSS, JavaScript, C#, ASP.NET, SQL, PHP