JavaScript - get number of days in month

3 points
Created by:

In this article, we would like to show you how to get the number of days in the month in JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

const getMonthDaysCount = ( => {
    const tmp = new Date(;
    tmp.setMonth(tmp.getMonth() + 1);
    return tmp.getDate();

// Usage example:

console.log(getMonthDaysCount('Mon Sep 02 2021'));  // 30
console.log(getMonthDaysCount('2021-09-02'));       // 30
console.log(getMonthDaysCount('2021-09'));          // 30
console.log(getMonthDaysCount(2021, 10));           // 30 <- Date(year, monthm, date) constructor used
console.log(getMonthDaysCount(new Date()));         // depending on current date
console.log(getMonthDaysCount(;         // depending on current date



In the above example, we use Date class constructor that applies different variants: date string, date-time string, date, and date-time components as arguments (year, month, day, hours, minutes, seconds, milliseconds). By using we forward getMonthDaysCount() arguments to Date class. Months are counted from 0 to 11, days from 1 up to 31 depending on the month. Creating Date class object with 0 as the day we achieve date that indicates last day of the previous month - that trick was used to get the number of days in the month.

Related posts

Alternative titles

  1. JavaScript - check number of days in month
Donate to Dirask
Our content is created by volunteers - like Wikipedia. If you think, the things we do are good, donate us. Thanks!
Join to our subscribers to be up to date with content, news and offers.
Native Advertising
Get your tech brand or product in front of software developers.
For more information Contact us
Dirask - we help you to
solve coding problems.
Ask question.

❤️💻 🙂