JavaScript How to Convert Number to String Easily

In JavaScript, convert a number to a string by using number.toString() or the String(number) function.

Examples

Input123

Output"123"

Input0

Output"0"

Input-45.67

Output"-45.67"

How to Think About It

To convert a number to a string, think about changing the number into text form so it can be used where words are needed. You can do this by calling a method on the number or by using a function that turns any value into a string.

Algorithm

1

Get the number you want to convert.

2

Use the number's toString() method or the String() function to convert it.

3

Return or use the resulting string.

Code

javascript

const num = 123;
const str1 = num.toString();
const str2 = String(num);
console.log(str1);
console.log(str2);

Output

123
123

Dry Run

Let's trace converting the number 123 to a string using toString()

1

Start with number

num = 123

2

Call toString()

str1 = num.toString() -> "123"

3

Print result

console.log(str1) outputs "123"

Step	Value
Initial number	123
After toString()	"123"
Output	"123"

Why This Works

Step 1: Using toString() method

The toString() method converts the number into its text form.

Step 2: Using String() function

The String() function takes any value and returns its string version.

Alternative Approaches

Template literals

javascript

const num = 123;
const str = `${num}`;
console.log(str);

Easy and readable, but uses string interpolation which may be less obvious for beginners.

Concatenation with empty string

javascript

const num = 123;
const str = num + '';
console.log(str);

Quick trick to convert number to string by adding an empty string, but less explicit.

Complexity: O(1) time, O(1) space

Time Complexity

Conversion is a simple operation that takes constant time regardless of the number size.

Space Complexity

Only a new string is created, so space used is constant and minimal.

Which Approach is Fastest?

All methods like toString(), String(), template literals, and concatenation run in constant time with negligible differences.

Approach	Time	Space	Best For
toString()	O(1)	O(1)	Clear and explicit conversion
String()	O(1)	O(1)	Converts any value, not just numbers
Template literals	O(1)	O(1)	Readable and flexible string creation
Concatenation with ''	O(1)	O(1)	Quick shorthand but less explicit