Dates & durations
Days Between Dates Calculator
Count calendar days between dates, with an option to include the end date.
Open tool →Dates & durations
Add or Subtract from a Date
Add or subtract days, weeks, months or years. Includes 30, 60, 90 and 100-day shortcuts.
1
Your dates
On this deviceYour dates are remembered here for 30 days. No account needed.
2
Your story in numbers
Every date has a story.
Enter your dates to discover your result and the next dates worth keeping.
Understanding your result
Days and weeks shift by a fixed day count. Months and years preserve the day where possible, otherwise clamp it to month end. Adding one month to January 31 can therefore give February 28 or 29.
See a worked example
Illustrative example, as of September 13, 2026.
- Date to explore
- 2026-09-13
- Number
- 30
- Unit
- days
- Operation
- 1
October 13, 2026
Are my dates sent to a server?
Calculations run in your browser. Your dates stay on this device unless you choose to include them in a sharing link or image. “Clear my dates” removes them from local storage.