Business Day Calculator
What Is a Business Day?
A business day is typically any working weekday, Monday through Friday, that is not a public holiday. When you plan projects, payment terms, or shipping estimates, you often care about how many business days fall between two dates rather than the total calendar days.
For example, a 30 calendar day window might contain several weekends and holidays, leaving far fewer actual workdays than you expect. Counting true business days helps you set realistic deadlines, allocate staff, and communicate accurate timelines to clients, suppliers, and stakeholders.
How to Use the Business Day Calculator
- Choose a Start Date using the date picker labeled “Start Date.” This is the first day you want to include in your calculation.
- Choose an End Date using the date picker labeled “End Date.” This is the final day in the range you care about.
- Optionally enter Holidays in the field “Holidays (comma-separated YYYY-MM-DD).” Add any dates that should be treated as non-working days, separated by commas. For example:
2025-01-01, 2025-01-20, 2025-02-17. - Set Hours per Business Day if you want to translate workdays into work hours. By default this is 8 hours, but you can change it to match your schedule (for example, 7.5 or 10 hours per day).
- Click Calculate Workdays to see the total business days and, if supported in the results, the equivalent total work hours.
The calculator treats both the start and end dates as business days if they fall on a weekday and are not listed as holidays.
How the Business Day Calculation Works
The calculator conceptually checks every date between your chosen start and end dates. For each date, it decides whether to include it as a business day based on two simple rules:
- Weekend rule: Saturdays and Sundays are always excluded.
- Holiday rule: Any date that matches one of the holidays you entered is excluded as well.
If a date is a weekday and not on your holiday list, it is counted as one business day.
In formula terms, you can think of the core logic like this:
Here, I(condition) is an indicator function that equals 1 when the condition is true (the date is a working day) and 0 when it is false (the date is a weekend or holiday). The calculator adds up these 1s and 0s to get the total business day count.
If you provide an “Hours per Business Day” value, you can also derive total work hours:
Total work hours = Business days × Hours per business day
Interpreting the Results
After you click the calculate button, you will typically see at least one of the following outputs:
- Total business days: The count of weekdays between your start and end dates, excluding any holidays you entered.
- Total work hours (if shown): The business day total multiplied by the “Hours per Business Day” value.
Keep in mind:
- If the end date is earlier than the start date, the calculator may automatically reverse them so the count is always non-negative.
- If you leave the holiday field empty, only weekends will be excluded.
- If you set the hours per business day to 0, the business day count is still valid, but the total work hours will be zero.
Worked Example
Suppose you are planning a short project that runs from April 1, 2025 to April 14, 2025, and your company observes April 4, 2025 as a holiday. You work 8 hours per business day.
- Set Start Date to 2025-04-01.
- Set End Date to 2025-04-14.
- Enter
2025-04-04in the holidays field. - Leave Hours per Business Day at 8.
- Click Calculate Workdays.
From April 1 to April 14 inclusive, there are 14 calendar days. Within that range, the weekends are April 5–6 and April 12–13, and April 4 is a holiday.
- Calendar days: 14
- Weekend days: 4 (two Saturdays and two Sundays)
- Holidays: 1 (April 4)
The calculator counts 14 minus 4 weekends minus 1 holiday, for a total of 9 business days. With an 8-hour workday, that equals 72 work hours. This gives you a clear view of the actual working time you have available for the project.
Business Days vs. Calendar Days
The table below contrasts business day calculations with simple calendar day counts, and compares manual counting to using this calculator.
| Method / Concept | What it Counts | Typical Use Cases | Pros | Cons |
|---|---|---|---|---|
| Calendar days | Every day between two dates, including weekends and holidays. | High-level scheduling, personal timelines, basic durations. | Simple, quick to understand, matches calendar pages. | Does not reflect actual working time; may overestimate capacity. |
| Business days | Weekdays (Mon–Fri) that are not holidays. | Project planning, SLAs, payment terms, HR policies, shipping estimates. | Aligns with real working time and operational commitments. | Requires tracking holidays and work schedules. |
| Manual counting | Hand-marked days on a calendar or basic spreadsheet formulas. | One-off calculations with few dates and no custom hours. | No tools required; familiar for many users. | Slow, error-prone, and awkward when many holidays or long ranges are involved. |
| This calculator | Business days, with optional holidays and hours per day. | Any situation where you need a fast, repeatable business day count. | Quick, consistent, handles custom holidays, runs in your browser. | Assumes a Monday–Friday workweek and only excludes holidays you specify. |
Common Uses for Business Day Calculations
- Project management: Estimate how many working days are available before a milestone, or how many business days you need to complete specific tasks.
- Finance and billing: Work out payment terms such as “net 10 business days” or “payment will be processed within 3 business days” after receipt.
- HR and staffing: Calculate notice periods, onboarding schedules, or the number of working days in a probation period.
- Operations and logistics: Estimate shipping, handling, or approval times that are specified in business days rather than calendar days.
Assumptions and Limitations
This calculator is designed to be straightforward and general-purpose. To keep it simple, it uses a few key assumptions:
- Fixed workweek: Business days are Monday through Friday only. Saturdays and Sundays are always treated as non-working days.
- User-specified holidays only: The tool does not automatically apply national, regional, or religious holidays. You must enter any non-working dates you want excluded.
- Inclusive dates: The start and end dates are included in the business day count if they fall on a weekday and are not holidays.
- No time-of-day handling: The calculator works with whole days, not hours and minutes. Partial days are approximated via the “Hours per Business Day” setting, not by start or end times.
- Standard work schedule: The same hours per business day value is applied to every business day in the range; varying daily schedules are not modeled.
If your organization uses a different workweek (for example, Sunday to Thursday) or has complex shift patterns, you may need to adjust the results manually or use a more specialized scheduling tool.
Quick FAQ
Do business days include holidays?
No. Any date you enter in the holidays field is excluded from the business day count, even if it falls on a weekday.
Are weekends always excluded?
Yes. Saturdays and Sundays are always treated as non-working days in this calculator.
Can I use this calculator for international holidays?
Yes, as long as you manually enter the relevant holiday dates in YYYY-MM-DD format. The tool does not automatically know which country you are in or which holidays you observe.
What happens if I swap the start and end dates?
If the end date is earlier than the start date, the calculator can reverse them internally so that you still get a positive business day count for the range.
How does the hours per business day setting affect results?
The hours per business day value is used to convert business days into total work hours. It does not change which days are counted as business days; it simply scales the time estimate.