Formula & assumptions
Calendar days = end date − start date + optional inclusive day
Elapsed-day counting gives the number of midnight boundaries between two dates. Inclusive counting adds one to count both endpoint dates. The tool counts all calendar days and uses UTC date arithmetic, so local daylight saving transitions do not turn a day into 23 or 25 hours. It does not subtract public holidays or weekends.
Worked example
EXAMPLE
January 1 to January 31 is 30 elapsed days, or 31 inclusive dates. Thirty days can also be written as four whole weeks and two remaining days.
How to use this calculator
- Select a start date and an end date on or after it.
- Choose elapsed or inclusive counting.
- Read the total days and the whole-week breakdown.
Frequently asked questions
What does the same start and end date return?
Zero elapsed days or one inclusive date.
Are leap days included?
Yes. February 28 to March 1 in a leap year is two elapsed days.
Is this a working-day calculator?
No. Weekends and holidays are included, so the result is not a deadline under a particular country’s business-day rules.