Date Difference Calculator
Calculate date differences
What Is This Tool?
The Date Difference Calculator finds the number of days between two dates, plus a calendar-aware breakdown into years, months, and days (not just a simple days-divided-by-30 estimate), along with total weeks and total hours for quick reference.
How to Use
Pick a start date and an end date — either order works.
Click Calculate to see the total day count and the years/months/days breakdown.
Copy the result summary for notes, reports, or documentation.
Features
- Calendar-aware years/months/days breakdown, not a fixed 30-day estimate
- Total days, weeks, and hours between the two dates
- Works regardless of which date is entered first
- Handles varying month lengths and leap years correctly
- Copy the result summary with one click
- 100% client-side — nothing leaves your browser
Examples
Start: 2026-01-15 End: 2026-06-02
Output: Total days: 138 · Breakdown: 4 months, 18 days · Total weeks: 19.71 · Total hours: 3,312
Common Use Cases
- Calculating project duration or time until a deadline
- Working out how long ago an event happened
- Measuring the length of an employment period or subscription
- Planning event countdowns in days, weeks, or hours
Frequently Asked Questions
Why is the years/months/days breakdown different from dividing total days by 30?
This tool walks actual calendar months, which vary from 28 to 31 days, rather than assuming every month is 30 days, so the breakdown matches how a calendar actually works.
Does it matter which date I put first?
No. If the end date is earlier than the start date, the tool automatically swaps them so the result is always a positive difference.
Does this account for time zones?
The calculator treats both dates as calendar dates (no time-of-day component) and computes the difference in UTC, so results are the same regardless of your local time zone.
Are leap years handled correctly?
Yes, the day-borrowing logic used for the years/months/days breakdown correctly accounts for February having 29 days in a leap year.
Is my date data sent anywhere?
No. All calculations happen locally in JavaScript in your browser. Nothing is uploaded or logged.
What's the difference between Total Weeks and the years/months/days breakdown?
Total Weeks is simply total days divided by 7 shown to two decimal places, while the years/months/days breakdown is a calendar-aware decomposition. Both describe the same span, just in different units.