Days between dates and adding days to a date
Days between two dates is the end date minus the start date. A future end date shows how many days are left; a past one shows how many days have passed.
For anniversaries and milestones such as a baby's 100th day, the first day counts as day 1, so day 100 falls 99 days after the start date.
The days-between result does not count the start date (May 1 to May 2 is 1 day). If you count the start date as day 1, as people do for anniversaries or "day 100", add one.
If the start date is day 1, the 100th day is 99 days after it. Choose "Count start date as day 1" under Add days to a date and the calculator handles this for you.
Yes. Enter a negative number of days to find a date in the past.