Business Days Calculator
Count working days between dates, or add and subtract them. Choose your workweek and closures, with a transparent date-by-date breakdown.
A calendar you can account for
View the formulas ↗Choose the calculation
Count a date range or move forward or backward a set number of working days.
Define a working day
Select your weekdays, an optional standard US federal holiday calendar and custom closure dates.
Inspect the dates
Check the endpoint convention and see exactly which dates counted. Download the full schedule.
Small details. Better estimates.
Explore all 6 guides ↗Business days versus calendar days: count a real timeline
See how weekends, holidays and endpoint choices change a business-day count, with a worked November example.
Read the guide ↗Guide 02 / Worked examplesAdd or subtract business days without an off-by-one error
Understand day zero, weekend starts, zero-day offsets and backward scheduling through a worked five-day example.
Read the guide ↗Guide 03 / Worked examplesObserved federal holidays and the December 31 edge case
Understand observed dates, cross-year New Year holidays and the limits of a recurring US federal holiday preset.
Read the guide ↗Guide 04 / Worked examplesCustom weekends and company closures: build the calendar you use
Plan a Sunday–Thursday week or a company shutdown without double-counting dates or assuming federal employee rules.
Read the guide ↗Guide 05 / Worked examplesWhy daylight saving and leap years should not confuse a workday count
See why a date-only calculator counts civil dates instead of dividing hours by 24, with leap-day and DST examples.
Read the guide ↗Guide 06 / Worked examplesPlan a project handoff with a transparent working-day schedule
Build a two-stage project timeline, show the counted dates and separate processing time from an explicit buffer.
Read the guide ↗Before you calculate
Is the starting date counted?
For a range, you choose whether each endpoint is included. For adding or subtracting, the start is day zero; counting begins on the next or previous date.
Which holidays are included?
The optional preset uses recurring US federal holidays observed on the standard Monday–Friday schedule. It excludes one-off closures and Inauguration Day. It is not a universal company or legal calendar.
Can I use Sunday through Thursday?
Yes. Select those working weekdays. The federal preset still uses standard Monday–Friday observed dates; use custom closures for a different local or company calendar.
Will daylight saving change the answer?
No. The calculation uses calendar-date arithmetic in UTC, not elapsed local hours. Dates are supported from 2000 through 2100.