Date Difference Calculator
Calculate the exact number of days, weeks, months and years between two dates — or add/subtract any number of days from a date to find a deadline, due date or countdown target.
Difference between two dates
8m 11d = 254 days total
Weeks + days
36w 2d
Total days
254
Total hours
6,096
Add / subtract days from a date
Resulting date
Monday, October 12, 2026
How it works
The difference between two dates is computed in calendar terms (years, months, days) the same way ages are counted, and also as a raw total of days using millisecond arithmetic on UTC-normalized dates. Adding days shifts the date by that many 24-hour periods on the calendar.
Frequently asked questions
Does the count include the end date?
The exclusive difference is shown by default (e.g. Jan 1 → Jan 2 = 1 day). Toggle 'include end date' to add one.
Are leap years handled?
Yes. All arithmetic uses the built-in calendar, so February 29 in leap years is counted correctly.