What is this calculator?
Counts the business days between two dates by walking the calendar day by day and excluding Saturdays, Sundays, and any holidays you supply. It reports what it excluded and why, so the number is auditable rather than a bare total.
Use it when:
- You are calculating a delivery or SLA date in business days.
- You need to count billable or working days for a project or invoice.
- You want to know how many working days a leave period actually consumes.
Intended for: Project managers, HR and payroll staff, and anyone planning against business days.
How is this calculated?
- The range is first narrowed according to your include-start and include-end choices, so you control exactly which dates are considered.
- Every date in that range is then visited individually — there is no formula shortcut, because holidays fall wherever they fall.
- Each date is classified in order: a Saturday or Sunday is counted as a weekend exclusion; otherwise, if it matches a date in your holiday list, it is counted as a holiday exclusion; otherwise it is a working day.
- Testing weekends first means a holiday that falls on a weekend is not double-counted — it is reported once, as a weekend day.
- The result reports working days alongside the calendar days considered and the counts excluded for each reason, so the arithmetic can be checked.
Formula
Working days
Working days = Days considered − Weekend days − Holidays on weekdays
The three reported counts always reconcile, which is what makes the result auditable.
Example
From Monday 2026-01-05 to Friday 2026-01-16, including the start date and the end date, with 2026-01-14 as a holiday.
- 12 calendar days are considered.
- 2 of them (10 and 11 January) are a weekend.
- 1 more (14 January) is a weekday holiday.
Result: 9 working days — 12 considered, less 2 weekend days and 1 holiday.
Frequently asked questions
Which days count as the weekend?
Saturday and Sunday. Regions with a different working week (for example Friday–Saturday) are not currently configurable, though a non-standard rest day can be entered in the holiday list as a workaround.
Are public holidays included automatically?
No, and deliberately so. Holidays vary by country, state, and even by employer, and they change every year. Supplying them yourself keeps the count correct instead of silently using the wrong calendar.
What happens to a holiday that falls on a weekend?
It is counted once, as a weekend day. It is not deducted twice, and no substitute weekday is added — if your jurisdiction grants one, add that substitute date to the holiday list.
Why can I control the start and end inclusion separately?
Because conventions differ. An SLA often excludes the day a ticket is raised but includes the resolution day; a leave request usually includes both. Separate switches let you match your own rule exactly.
Assumptions
What this calculator takes as given:
- Dates are treated as civil calendar dates (year, month, day) with no time-of-day component.
- No time zone is applied, so a date means the same thing wherever you are — the result never shifts by a day depending on your location.
- The proleptic Gregorian calendar is used throughout, including for dates before its historical adoption.
- The weekend is Saturday and Sunday.
- Holidays are supplied by you; the calculator holds no holiday calendar for any country.
- A holiday falling on a weekend is counted once, as a weekend day.
Limitations
What this calculator cannot know or does not model:
- Non-standard working weeks are not configurable.
- No built-in public-holiday calendar exists for any jurisdiction.
- Half-days, shift patterns, and partial working days are not modelled.
- Regional substitute or observed holidays must be entered explicitly.