Count days between dates or shift a date. This free date calculator finds the days (and weeks) between two dates, or adds/subtracts days to land on a new date, showing the resulting weekday.
Pick two dates to count the days (and weeks) between them. The end date can be earlier than the start – the result will simply be negative.
Pick a date, then add or subtract a number of days to find the resulting date.
Days between counts the nights from the start date to the end date. “Including the end day” adds one, which is how you’d count inclusive spans like a holiday or hotel stay differently from nights.
What This Date Calculator Does
This calculator works two ways: count the exact number of days (and weeks) between two dates, or start from a date and add or subtract a number of days to find the resulting date, along with its day of the week.
Days Between Two Dates
Pick a start and end date, and the calculator shows the exact number of days between them, along with total weeks, a weeks-and-days breakdown, and an inclusive count that adds one for spans like a hotel stay or event.
For example, from January 1 to April 1 in the same year is exactly 90 days.
Adding or Subtracting Days From a Date
Pick a starting date, choose add or subtract, and enter a number of days to find the resulting date and its day of the week – useful for deadlines, due dates, or any “X days from now” calculation.
For example, 90 days after January 1, 2026 lands on Wednesday, April 1, 2026.
Why the Resulting Day of the Week Matters
A deadline calculated as “90 days from today” is far more useful once you know which day of the week it actually falls on – a Saturday deadline behaves very differently from a Wednesday one for business purposes.
Negative Results Are Expected, Not Errors
If the end date is earlier than the start date, the day count simply comes back negative rather than showing an error – useful for checking how long ago a past date was relative to another date.
Common Uses for This Calculator
This calculator is useful for tracking deadlines, calculating due dates, planning events a set number of days out, checking contract or notice periods, and general day-counting for both past and future dates.
How to Use the Date Calculator
- Choose a mode: Days Between, or Add/Subtract.
- Enter your dates (or a date and number of days).
- Review the result, including the day of the week.
Need to calculate hours worked instead? See our Hours Calculator.