Business Days Calculator
Count the business days (Monday-Friday) between two dates. Leave the start date blank to count from today, pick whether the start day itself counts, and get the weekday-only total alongside calendar days and working weeks.
Business days here are Mondays through Fridays. Federal holidays (about 11 per year) are not subtracted — pull out any that fall in your window if your deadline skips them.
Counting weekdays without the off-by-one
The mechanical rule: full weeks contribute exactly 5 business days each, and the leftover days depend on which weekday you start from. The bigger source of error is the endpoint convention. Deadlines usually exclude the trigger day and include the due day ('within 10 business days' starts counting tomorrow); shared workdays between two dates often include both. This tool defaults to exclude-start/include-end and lets you flip it — the answer changes by exactly one weekday when the start falls on a Monday-Friday.
Holidays are the other adjustment. Mondays through Fridays here all count; US federal holidays average about one per month, so subtract any that land inside your window if the contract or court rule excludes them.
How it’s calculated
Calendar days = round((end − start) / 86,400,000 ms), both dates at noon. Business days = the count of days with weekday Mon-Fri, stepping one day at a time from the day after the start through the end date (the 'both' option also counts the start day when it's a weekday). Working weeks = business days ÷ 5. Dates entered in reverse order are swapped and flagged.
No holiday exclusions — federal, state, and court holiday calendars differ, so subtract the ones that apply to your deadline.
Business days in selected 2026 months (before holidays)
| Month | Calendar days | Business days |
|---|---|---|
| January 2026 | 31 | 22 |
| February 2026 | 28 | 20 |
| March 2026 | 31 | 22 |
| July 2026 | 31 | 23 |
| December 2026 | 31 | 23 |
Computed from the 2026 calendar, Mon-Fri only; subtract observed holidays such as Jan 1, Jul 3 (July 4 observed), and Dec 25 where they apply.
Common mistakes
- Counting the start date as a business day when the deadline says 'within N business days' — the clock usually starts the next weekday.
- Forgetting holidays: 30 business days spanning late November silently includes Thanksgiving unless you remove it.
- Dividing calendar days by 7 and multiplying by 5 — the leftover partial week can add up to 5 weekdays depending on alignment.
- Assuming Saturday deliveries or court filings count; business-day definitions are Mon-Fri in nearly all US contexts.
Frequently asked questions
How do you count business days between two dates?
Step through the calendar from the day after the start through the end date and count every Monday-Friday: business days = weekdays in (start, end]. Full weeks contribute 5 each; the remainder depends on the starting weekday.
Do the start and end dates count?
Convention varies. Deadlines typically exclude the start day and include the end day (this tool's default); shared-workday counts often include both. The toggle switches conventions — they differ by at most one day.
Are holidays excluded?
No — this counts all Mondays through Fridays. US federal holidays run about 11 per year; subtract any that fall in your range if the rule you're following skips them. Courts and states keep their own lists.
How many business days until May 21 without weekends?
From May 1 of 2026 (a Friday), May 21 is 14 business days away excluding the start day — 20 calendar days minus 6 weekend days. From a different date, the tool recounts exactly.