How to add leading zero to a number in JavaScript
I had the need to add a leading zero when the number I had was less than 10, so instead of printing “9” on the screen, I had “09”.
The use case being I wanted to display the length of a video, and 5:04 is more logical than 5:4 to say a video is 5 minutes and 4 seconds.
Here’s how I did it:
Math.floor(mynumber)
.toString()
.padStart(2, '0')
All of this is native to JavaScript, using the Math built-in library
→ Get my JavaScript Beginner's Handbook
I wrote 17 books to help you become a better developer, download them all at $0 cost by joining my newsletter
- C Handbook
- Command Line Handbook
- CSS Handbook
- Express Handbook
- Git Cheat Sheet
- Go Handbook
- HTML Handbook
- JS Handbook
- Laravel Handbook
- Next.js Handbook
- Node.js Handbook
- PHP Handbook
- Python Handbook
- React Handbook
- SQL Handbook
- Svelte Handbook
- Swift Handbook
JOIN MY CODING BOOTCAMP, an amazing cohort course that will be a huge step up in your coding career - covering React, Next.js - next edition February 2025