Business Days Calculator
Count Monday–Friday business days or shift a date while excluding your own observed holidays.
Content updated August 4, 2026
This is not a universal legal, banking, exchange, or delivery calendar. It treats Saturday and Sunday as weekends and only excludes the holiday dates you enter.
Count business days in an inclusive date range, or add and subtract a signed number of business days from a starting date. The calculator uses a clearly defined Monday–Friday workweek, skips Saturdays and Sundays, and can exclude observed holiday dates that you provide.
Holiday calendars vary by country, institution, employer, exchange, and even work schedule. Instead of silently applying the wrong jurisdiction, this tool leaves the list under your control and shows how many entered weekday holidays changed the count.
The Business Days formula
Business days = Monday–Friday dates in the selected interval − distinct entered holidays that fall on those weekdaysRange mode includes both endpoints · shift mode excludes the start date · positive shifts move forward · negative shifts move backward.
Worked example
From Monday, August 3, 2026 through Friday, August 14, 2026 there are 12 inclusive calendar dates and 10 Monday–Friday weekdays. With no entered holidays, the result is 10 business days. Adding 10 business days to August 3, without counting that start date, lands on August 17.
Assumptions, rounding, and limitations
Assumptions
- The workweek is Monday through Friday; Saturday and Sunday are nonbusiness days.
- Range mode includes both the start and end dates, while shift mode does not count the starting date.
- Holiday input contains the observed YYYY-MM-DD dates relevant to the user's own calendar.
- Dates are treated as calendar dates without a time of day or time-zone conversion.
Rounding: No rounding is used. Calendar dates, weekday counts, and signed shifts are handled as whole values; duplicate holiday entries are deduplicated before calculation.
Limitations
- The tool does not automatically supply or validate any jurisdiction's holiday, market, banking, court, school, employer, or delivery calendar.
- It does not model nonstandard workweeks, half-days, emergency closures, time cutoffs, settlement rules, or local time zones.
- Date ranges are limited to 100 years, shifts to 100,000 business days, and holiday lists to 500 entries.
Sources
- Federal Holidays — U.S. Office of Personnel Management
- Federal Holidays — In Lieu Of Determination — U.S. Office of Personnel Management
Counting a range versus shifting a date
Range mode includes both endpoints. It examines each calendar date, counts Monday through Friday as weekdays, then removes distinct entered holidays that fall on those weekdays. A holiday on Saturday or Sunday cannot reduce the total twice.
Shift mode does not count the starting date. A shift of +1 moves to the next eligible business day, −1 moves to the previous eligible business day, and zero returns the original date.
Observed holidays need an explicit calendar
An official holiday and its observed nonworkday are not always the same date. For example, the U.S. Office of Personnel Management explains that, for most Monday–Friday federal employees, a Saturday holiday is usually observed on Friday and a Sunday holiday on Monday.
Enter the observed dates that apply to your purpose in YYYY-MM-DD form. The calculator does not infer federal, provincial, state, banking, securities-market, school, religious, employer, shipping, or court closures.
Frequently asked questions
▶Does the business-day count include the start and end dates?
Yes. Range mode includes both dates when they are eligible Monday–Friday days and are not entered holidays.
▶Does adding one business day count the start date?
No. Shift mode starts counting after the starting date, so +1 means the next eligible business day.
▶Are public holidays included automatically?
No. Enter the observed YYYY-MM-DD holiday dates for your own calendar; leaving the field blank excludes only Saturdays and Sundays.
▶What happens if I enter a holiday on a weekend?
It does not reduce the count because Saturday and Sunday are already excluded. Enter the observed weekday as well when your calendar uses one.
▶Can I subtract business days?
Yes. Choose add or subtract mode and enter a negative whole number, such as −5, to move backward five eligible business days.
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Open calculator →Disclaimer: Business Days Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.