Date Calculator: Days Between Dates, Add & Subtract Days
Find the calendar-day difference between dates, count both endpoints, or add and subtract whole calendar days. Weekends and holidays remain included. These are date-only calculations in the Gregorian calendar.
Calendar date calculator
How many days are between two dates?
The elapsed difference counts calendar-day transitions and treats the start date as day zero. November 2 to November 6, 2026, is 4 elapsed days. When both endpoints are counted as dates in a list, the same interval contains 5 calendar dates. Select the checkbox only when that inclusive convention matches your question.
Same-day and reversed ranges
For the same start and end date, the elapsed difference is 0 and the inclusive count is 1. This calculator rejects reversed between-date ranges rather than silently swapping them or producing a negative duration. To move backward from a date, choose Add or subtract calendar days and select Subtract days.
Add days to a date
Adding 10 calendar days to November 2, 2026, gives November 12, 2026. Adding 3 calendar days to Friday, November 6, gives Monday, November 9. Saturday and Sunday remain part of the calculation. These examples are arithmetic demonstrations, not delivery or deadline rules.
Subtract days from a date
Subtracting 10 calendar days from November 12, 2026, returns November 2, 2026. The starting date is not counted as the first day moved in either direction. If you need an inclusive list of dates rather than a date offset, use the between-dates mode with its inclusive option.
Leap years and daylight-saving time
The calendar handles actual month lengths and Gregorian leap years. February 28 to March 1 is 2 elapsed days in 2028 but 1 in 2027. Dates are processed as calendar values, so daylight-saving changes do not add or remove a counted day. This is not an elapsed-hours or timestamp calculator.
What about months, years, or weeks?
The difference result also expresses the selected count as complete groups of 7 days plus remaining days. It does not count calendar-week boundaries. Months and years are not converted from days using a fixed divisor: completed months and end-of-month adjustments require a separately defined convention.
Does this calculate business days?
No. Calendar days include weekends and holidays. For a working-calendar question, use explicit excluded weekdays and closures rather than assuming a calendar-day difference matches a business-day count. Governing legal, financial, or contractual rules may also specify boundaries, holidays, and cutoff times that this tool does not determine.
Date calculation guide
How to calculate days between dates and add or subtract days explains the conventions with examples.
Working-calendar guide
How to calculate business days between two dates covers weekends, closures, and endpoint inclusion.
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