Date Difference Calculator
Calculate exact calendar days, business days, and weeks between two dates.
Enter dates to exclude from business days (comma or line separated, YYYY-MM-DD).
Calculation Methodology & Counting Rules
The Date Difference Calculator calculates the exact elapsed time between two calendar dates in total days, weeks, business days (Monday through Friday), and weekend days.
The tool converts Gregorian calendar dates directly to civil epoch day numbers to calculate elapsed duration without timezone distortion or daylight saving shifts. Business days count Mondays through Fridays, skipping Saturdays and Sundays and any user-specified holiday dates.
Counting Conventions & Assumptions
- Uses the Gregorian calendar with leap-year cycle rules (divisible by 4, except 100 unless 400).
- Standard exclusive counting counts [start, end), where the start date is included and end date is excluded.
- Inclusive counting counts both start date and end date as full active days [start, end].
- Business days default to Monday through Friday without assuming country-specific statutory holiday calendars unless explicitly entered by the user.
From Monday, October 19, 2026 to Monday, October 26, 2026 (inclusive).
Difference in calendar days: 7 days + 1 (inclusive) = 8 calendar days.
Weekdays (Mon–Fri): 6 business days (Mon 19, Tue 20, Wed 21, Thu 22, Fri 23, Mon 26).
Weekend days: 2 days (Sat 24, Sun 25).
Result: 8 calendar days, 1 week and 1 day, 6 business days, 2 weekend days.
From January 1, 2026 to January 15, 2026 (exclusive).
Difference in calendar days: 15 - 1 = 14 calendar days.
Completed weeks: 2 weeks and 0 days.
Weekdays: 10 business days (Mondays through Fridays).
Weekend days: 4 weekend days.
Result: 14 calendar days, 2 weeks, 10 business days, 4 weekend days.
Frequently Asked Questions
Does this calculator include both the start and end date?
By default, standard calendar difference is exclusive (counting elapsed days from start up to end). You can check 'Include End Date' to count both endpoint dates as full active days.
How are business days calculated?
Business days include Mondays through Fridays, skipping Saturdays and Sundays. If you provide specific holiday dates, they are also subtracted from the business-day total.