Business Days Calculator
Count the number of working days (weekdays) between two dates, excluding weekends and optionally public holidays. Add or subtract business days from a date.
What Is the Business Days Calculator?
The business days calculator counts the number of working weekdays (Monday–Friday) between two dates, excluding weekends. It also supports adding or subtracting a number of business days from a start date — useful for calculating deadlines, delivery estimates, payment due dates, and contract periods.
Formula
How to Use
Choose a mode: Count days between two dates, or Add/subtract business days from a date. For the count mode, enter a start and end date and optionally enter holiday dates to exclude. For the add/subtract mode, enter a start date and the number of business days to add or subtract.
Example Calculation
Count business days from 1 Jan 2025 to 31 Jan 2025: 31 calendar days, minus 8 weekend days (4 Saturdays + 4 Sundays) = 23 business days (before holidays).
Understanding Business Days
Business day calculations are essential in finance (T+2 settlement for stock trades), law (response deadlines), logistics (delivery windows), and project management (sprint durations). A simple calendar day count often gives the wrong answer because weekends are non-working days.
The International Standards Organisation defines a business day as a day that is not a weekend or public holiday in the relevant jurisdiction. Because public holiday calendars differ by country, region, and even company, the holiday exclusion feature requires manual input of the specific dates to exclude.
Financial markets typically use T+2 settlement (trade date plus 2 business days) for equity trades and T+1 for government securities. Missing the settlement date results in a settlement fail, attracting penalties. Accurate business day counting is therefore operationally critical.
The SLA (Service Level Agreement) industry uses business hours rather than business days for response time commitments, but business day calculations are the foundation: SLA targets expressed in hours are anchored to the business day calendar.
Frequently Asked Questions
Are weekends always Saturday and Sunday?
This calculator uses the standard Mon–Fri business week. Some countries use Fri–Sat or Sat–Sun as the weekend. You can exclude specific dates manually using the holiday input to handle non-standard weeks.
How do I calculate a due date that is 30 business days from today?
Use the Add Business Days mode. Enter today as the start date and 30 as the number of business days to add. The calculator shows the resulting date, skipping all weekends.
Does this calculator account for public holidays?
Public holidays vary by country and region. You can manually enter specific holiday dates to exclude them from the count. Enter them as comma-separated dates in YYYY-MM-DD format.
Is the start date included in the count?
By default, the start date is excluded (counting begins from the next day). The end date is included. This matches the most common financial convention for settlement periods.
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