Time and planning
Count calendar days between two dates, with a weekday and weekend breakdown.
Total calendar days
Enter your dates, then select Calculate.
Public holidays are not removed from the weekday count. Your dates are calculated in your browser and are not sent to a server.
Looking for a date a set number of days from now? Add or subtract days from a date
2026-10-09 to 2026-10-12 = 3 days
Leave Include end date unchecked for a three-night stay: Friday, Saturday, and Sunday nights. The checkout date starts no additional night in this example.
If you are planning activities on both arrival and departure days, include the end date instead. You then have 4 calendar dates to plan for, while the stay is still three nights.
This counts dates, not check-in hours or accommodation charges.
2026-10-12 to 2026-10-16 = 5 days inclusive
Select Include end date when work is planned on both Monday and Friday. The result is 5 calendar days, all weekdays. Leaving it unchecked counts Monday through Thursday only: 4 days.
The weekday count does not know which of those dates your team actually works.
2 days, or 3 with the end included
Excluding the end counts Wednesday, February 28 and Thursday, February 29. Including the end also counts Friday, March 1.
Both versions contain only Monday–Friday dates.
For the Monday–Friday project above, suppose your office is closed on Tuesday, October 13. This calculator still reports 5 weekdays, because it only identifies Monday through Friday. If the other four dates are working days, your team has 4 available work dates.
To exclude that closure, open the Business Days Calculator, count between 2026-10-12 and 2026-10-16, select both Include start date and Include end date, choose Saturday–Sunday weekends, and enter 2026-10-13 under Holidays or other days off. Add any other closures from your own schedule; public holidays are not loaded automatically.
Use this Date Difference Calculator when you need all calendar dates or a simple weekday split. Use Business Days when weekends or specific closures must be excluded, and the Date Calculator when you already know how many days to add or subtract and need the resulting date.
To allocate a full-period cost to part of that period, use the Prorated Cost Calculator. It derives both day counts from your dates and applies their ratio to the amount. Check its end-date choice: both ends are included by default, while Date Difference initially excludes the end.
For a date of birth and a chosen reference date, use the Age Calculator to read age in years, months, and days, plus the next birthday and its countdown. Enter the birth date as Date of birth and the reference date as As-of date; an elapsed day count alone does not describe calendar age.
Date Difference and Business Days start with different endpoint choices. For Friday, 2026-10-02 to Sunday, 2026-10-04, the default results below both follow their stated rules. Business Days uses Saturday–Sunday weekends and no holidays in this comparison.
2 calendar days · 1 weekday
The counted dates are Friday, October 2 and Saturday, October 3. Friday is the one Monday–Friday date. Sunday, the end date, is excluded.
0 business days
The interval contains Saturday, October 3 and Sunday, October 4. Both are skipped as weekend days. Friday, the start date, is excluded.
In Business Days, choose Count business days, select Include start date, and clear Include end date. With Saturday–Sunday weekends and no holidays, this gives 1 business day, matching the weekday count here.
To count both endpoints instead, select Include end date here and both endpoint checkboxes in Business Days. Match the included dates before comparing weekday totals; custom weekends or holidays can still produce different working-day counts. This comparison concerns counts between two dates, not Business Days' add/subtract or date-range modes.
Each valid date has a position in a continuous sequence of calendar days. With the end excluded, total days = end position − start position. Including the end adds one day. Equal dates therefore produce zero days by default, or one day with the end included.
Divide the total by seven to find full weeks and the remaining days. Each full week contributes five weekdays and two weekend days. The calculator then checks the weekdays of the remaining dates. All results are exact whole-day counts.
The same Gregorian calendar rules apply throughout the supported range, including years before the calendar's introduction in 1582. This is called the proleptic Gregorian calendar. It does not reproduce historical local calendar changes or convert Julian calendar dates.
Gregorian leap years are divisible by four, except century years that are not divisible by 400. For example, 1900 and 2100 are common years, while 2000 is a leap year. Source: U.S. Naval Observatory — Introduction to Calendars.
Use the default to measure the difference between dates. Include the end date when counting every calendar date in a range, such as a schedule that includes both its first and last day. Check which convention your own task requires.
There is no difference between identical dates. With the end excluded, no dates are counted. Select Include end date to count that one date; it will appear as either one weekday or one weekend day.
It is only a Monday–Friday count. Public holidays, company closures, and local working-week patterns are not considered. A public holiday on a Monday is still included as a weekday. Use the Business Days Calculator to choose a weekend pattern and exclude your own holiday dates.
No. This calculator compares calendar dates without times or time zones. A calendar day is counted once even when a local clock change makes that day's actual elapsed time shorter or longer than 24 hours. The result is not an elapsed-hours measurement.
The calculator asks you to correct the end date. Select Swap dates to exchange the inputs, then Calculate again. It does not silently reverse the range or show a negative day count.
Valid Gregorian dates from 0001-01-01 through 9999-12-31 are supported. There is no year zero. Leap days must be valid for the entered year, and the same Gregorian rules are used even before 1582.