Date Difference Calculator
Find the exact time span between any two dates.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Date Difference Calculator
Select two dates and the calculator instantly shows the exact time span between them in days, weeks, months, years, and hours.
- Enter the start date. This can be any date in the past or future.
- Enter the end date. The calculator works in either direction, so the order does not matter.
- Read the results. The primary result shows days. The breakdown shows weeks (with decimals), whole calendar months, complete years, and total hours.
- Share the calculation. The Share button generates a URL with both dates pre-filled.
About the Date Difference Calculator
The day count uses the absolute difference between the two calendar dates, so selecting January 1 and January 31 gives 30 days (the gap between them). The month and year counts are calendar-based: they count complete calendar months and years, not just 30-day or 365-day approximations. The hour count multiplies the day count by 24.
Common uses include calculating how long ago an event happened, finding deadlines, determining contract durations, or calculating someone's age in days.
Frequently Asked Questions
How do I calculate the number of days between two dates?
Enter the two dates in the Start Date and End Date fields. The calculator subtracts the earlier date from the later date and returns the number of calendar days between them. For example, from January 1 to March 1 is 60 days in a non-leap year and 61 days in a leap year.
Why are the month and day counts different from just dividing days by 30?
Calendar months have different lengths (28, 29, 30, or 31 days), so dividing total days by 30 gives an approximation, not an exact count. This calculator counts actual calendar months, the same way you would count on a physical calendar. From January 15 to April 15 is exactly 3 months, regardless of how many days those months contain.
Does the calculator count the start and end dates?
The day count measures the gap between the two dates, not the number of days you would cross off on a calendar. So from January 1 to January 1 (same day) is 0 days, and from January 1 to January 2 is 1 day. If you need to count both the start and end day (inclusive), add 1 to the result.
Can I calculate dates in the future?
Yes. Enter any two dates, past or future, in either order. The calculator always returns a positive result regardless of which date is earlier. This makes it useful for project planning, counting down to deadlines, or estimating how far apart future events are.