Basically, I want to find the difference between two dates in various units. What’s the best way to do this in JavaScript?
What I’m sharing below is a very common and easy approach. Just calculate Date Difference in Milliseconds.
So… in JavaScript, Date objects can be subtracted directly, which returns the difference in milliseconds. You can then convert this to seconds, minutes, hours, or days.
How it works:
Subtracting dates gives the difference in milliseconds.
This approach is quick and works across modern browsers.
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const date1 = new Date('2025-05-01');
const date2 = new Date('2025-05-02');
// Difference in milliseconds
const diffMilliseconds = date2 - date1;
// Convert milliseconds to days (1 day = 86400000 ms)
const diffDays = diffMilliseconds / (1000 * 60 * 60 * 24);
console.log(diffDays); // Expected output: 1 day
Pro tip: Make sure to handle timezone differences if you need precise results.
Heya! I see there’s an answer already — but I think I know one more way: by using the Date object and getTime() for more flexibility.
If you want more control over the date comparison, using the getTime() method is a solid option. It returns the timestamp in milliseconds, which you can subtract and then calculate differences.
Quick tutorial:
getTime()ensures you’re working with numerical values that can be easily manipulated.- Works great for more granular control when dealing with dates.
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const date1 = new Date('2025-05-01');
const date2 = new Date('2025-05-02');
// Get timestamps
const diffMilliseconds = date2.getTime() - date1.getTime();
const diffDays = diffMilliseconds / (1000 * 60 * 60 * 24);
console.log(diffDays); // Expected output: 1 day
Note: Make sure both dates are in the same timezone to avoid unexpected results.
Enjoy 
Hello Neha!
If you’re working with local times and want to account for things like daylight savings time (DST) or locale-specific differences, Intl.DateTimeFormat can come in handy.
Why use it?
Intl.DateTimeFormat is useful for displaying localized dates. While this doesn’t directly calculate differences, you can combine it with date difference methods to show localized time differences.
Example:
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const date1 = new Date('2025-05-01T00:00:00');
const date2 = new Date('2025-05-02T12:00:00');
// Format dates
const formatter = new Intl.DateTimeFormat('en-US', { month: 'short', day: 'numeric', year: 'numeric' });
console.log(formatter.format(date1)); // May 1, 2025
console.log(formatter.format(date2)); // May 2, 2025
Great little helper for international-friendly apps or when your users span multiple timezones!