Calculators / Date difference calculator
Date difference calculator
Count calendar days between two dates, with clear inclusive counting.
All calendar days count, including weekends and holidays.
How to count days between dates
Elapsed days measures the number of date changes between your start and end. September 1 to September 16 is 15 days. For a list that counts every date in that range, including September 1 and September 16, select “Include both dates” to get 16 days.
Inclusive calendar-day count = elapsed days + 1
Example: a trip from Friday to Monday
September 4 to September 7, 2026 is 3 elapsed days. Counting Friday, Saturday, Sunday, and Monday gives 4 inclusive calendar days.
Turning days into weeks
Each complete week has seven days. For 16 days, divide by 7: the result is 2 complete weeks with 2 days remaining. This is a duration, not a count of named calendar weeks.
Leap years and daylight saving
February 28 to March 1, 2024 is 2 elapsed days because February 29 exists that year. In 2025 the same range is 1 day. The tool compares calendar dates independently of local time-zone changes, so a daylight saving transition does not add or remove a calendar day.
Choosing the right counting method
Elapsed days is useful for the gap between events. Inclusive counting can describe the number of dates covered by an activity. For contracts, filing deadlines, leave, or bookings, use the counting rule that applies to your situation; this tool does not interpret those rules.
Common questions
Are weekends excluded?
No. Saturdays, Sundays, and public holidays are included. This is not a business-day calculator.
What if both dates are the same?
Elapsed days is zero. With Include both dates selected, the result is one calendar day.
Can the end be before the start?
No. Reverse the dates to measure a positive interval. The calculator shows an error if the end is earlier.