### Introduction

How do you convert a string to a number in Node.js?

You can convert a string to a number in Node.js using any of these three methods: `Number()`

, `parseInt()`

, or `parseFloat()`

.

In this article, we'll go over each method and how to use them in your code.

Let's get started!

#### Table of Contents

## Method 1 - Number()

The first method we'll cover is the `Number()`

constructor that takes a value as a parameter and attempts to convert it to a number. If the value passed to the `Number()`

constructor can't be converted to a number, `NaN`

is returned.

Here's an example of how you'd use it in your code:

` ````
Number("25")
// returns 25 (typeof === number)
```

We pass a string value of `"25"`

to the `Number()`

constructor and it returns a new number value of `25`

. If you checked the `typeof`

value for the new value, you'd find that it was transformed successfully from a string to a number.

Here are some more examples with different variations of strings passed as arguments:

` ````
Number("25") // returns 25
Number("25.51") // returns 25.51
Number("25px") // returns NaN
Number("25.5something") // returns NaN
```

Pretty easy to work with, right?

## Method 2 - parseInt()

The `parseInt()`

is a function that parses a string and returns an integer with a specific radix. The function takes both a string and an optional radix integer value as parameters.

Here's a code example:

` ````
parseInt("25")
// returns 25 (typeof === number)
```

We give the `parseInt()`

function a `"25"`

string as a parameter and it returns a value of `25`

. And the new value is a number instead of a string.

Here are some additional examples with other variations of strings:

` ````
parseInt("25") // returns 25
parseInt("25.51") // returns 25
parseInt("25px") // returns 25
parseInt("25.5something") // returns 25
```

Unlike the previous `Number()`

method, notice that all of the four example strings were converted to a `25`

number value. In those cases, the `Number()`

method returned a value of `NaN`

instead.

## Method 3 - parseFloat()

The last method we'll go over is the `parseFloat()`

function that takes a string and converts it to a number with decimals (known as a point number).

Here's what it looks like in code:

` ````
parseFloat("25")
// returns 25 (typeof === number)
```

Just like the previous two examples, the `parseFloat()`

function takes a string of `"25"`

and converts it into a number value of `25`

.

And here are some additional examples using the same string variations as the other methods:

` ````
parseFloat("25") // returns 25
parseFloat("25.51") // returns 25.51
parseFloat("25px") // returns 25
parseFloat("25.5something") // returns 25.5
```

Notice that the results are very similar to the `parseInt()`

method, besides the fact that `parseFloat()`

conserves the decimal points on the string values it converts.

## Conclusion

In this article, we went over three different ways to convert a string to a number using Node.js. These methods included the following:

`Number()`

`parseInt()`

`parseFloat()`

Thanks for reading and happy coding!

Have any questions or comments about this article? You can contact me via email at nick@coderrocketfuel.com or on Twitter at @CoderRocketFuel.