Date Difference Calculator
Find the exact number of days, weeks, months, and years between two dates. Perfect for project timelines, event planning, or tracking elapsed time.
Part of our Date & Time Calculators collection.
Date Difference Calculator
Free online calculator
Results update automatically as you type
How to Use This Calculator
- 1
Enter the start date (the earlier date).
- 2
Enter the end date (the later date).
- 3
Instantly see the difference in days, weeks, months, and years.
- 4
You can also enter a future date to count down to an upcoming event.
How the Date Difference is Calculated
Difference = End Date − Start Date The result is broken down into total days, weeks, months (calendar-accurate), and years.
Example Calculation
Example: January 1 to December 31
Inputs
startDate: 2025-01-01endDate: 2025-12-31
Result
364 days (11 months, 30 days)
From January 1 to December 31, 2025 is 364 days — just short of a full year.
Frequently Asked Questions
Can I enter a future end date?
Yes. A future end date shows how many days remain — useful as a countdown.
Does it include the start and end day?
The calculator counts the gap between dates. Add 1 to include both endpoints.