Add Days to Date
Add any number of days to a starting date to find the resulting calendar date — useful for deadlines and due dates.
Also covers: date calculator add days
Add Days to Date
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View on AmazonHow the Add Days to Date works
- Choose what you want to do: add days, subtract days, or find days between two dates.
- Enter the date(s) involved.
- Read the resulting date or day count — leap years and varying month lengths are handled automatically.
Formula / logic
Days between = (later date − earlier date) in whole days. Add/subtract = start date shifted forward or backward by N days on the calendar.
Worked example
From January 1 to December 31 in a non-leap year is 364 days. Adding 30 days to January 1 lands on January 31.
Frequently asked questions
Can I add months or years instead of days?
Enter the equivalent number of days, or use whole-week increments (7, 14, 30) for quick approximations.
Does this account for leap years?
Yes, the calculation uses real calendar dates, so February 29 in a leap year is counted correctly.
Does 'days between' include both the start and end date?
The count reflects full days elapsed between the two dates; the start date itself counts as day zero.
Is the Add Days to Date free to use?
Yes — every calculator on this site is free, with no sign-up or download required.
Does the Add Days to Date work on mobile?
Yes, the layout and calculator both adapt to phone and tablet screens.