Federal holidays are cross-checked on every build against a second, separately written implementation of 5 U.S.C. 6103, for every year from 1978 to 9999. How it is checked
Count the working days between two dates, or add business days to a date. Weekends and US federal holidays come out, and the list under the answer names each day that was skipped, so you can check the count.
Which days the count includes
Two people asking how many days lie between the 1st and the 8th can want different answers: seven if they count the gap, eight if they count both dates.
A business-day count here covers the same span as the gap. It counts the start date and not the end date, and the sentence under the answer says so. This page has no setting for counting both ends, so check the convention when you compare the result with another count.
Why the arithmetic runs in whole days
A date here is a year, a month and a day, with no time of day attached. Every calculation converts to midnight UTC, does integer arithmetic on whole days, and converts back. That matters twice a year: local-time arithmetic across a daylight-saving change gains or loses an hour, and an hour is enough to land an answer on the wrong date. Local time is used only for the word "today", because that depends on where you are. The methodology page sets out these rules in full, including how the observed-date rule is applied.
Working days and federal holidays
Most shipping windows and legal deadlines count working days, with weekends and public holidays taken out, and that is the count this business days calculator makes. The holidays it removes are the federal ones, applied on the day they are observed; the full list for any year shows each of them beside the date the statute names.
Questions
Does the count include the start date or the end date?
Counting between two dates includes the start date and excludes the end date, which is the convention deadlines are written in: five business days from a Monday lands on the following Monday. Adding business days moves forward from the start date without counting it, so five business days after a Monday is that same following Monday. The two readings count different ends of the span, and every answer names the one it used.
Which holidays does it remove?
The eleven United States federal holidays, and nothing else: New Year’s Day, the Birthday of Martin Luther King Jr., Washington’s Birthday, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas. Each one is computed from its rule in 5 U.S.C. 6103, with no stored list of dates, so it comes out right in years nobody has typed in yet.
What happens when a holiday falls on a Saturday or Sunday?
The observed day comes out, which is the day offices close. Under 5 U.S.C. 6103(b) a holiday on a Saturday is observed the Friday before and one on a Sunday the Monday after, so Independence Day in 2026 falls on a Saturday and Friday the 3rd of July is the day removed. The page also handles a case that is easy to get wrong: when the 1st of January is a Saturday, the day off is the 31st of December of the previous year.
Why does my employer’s answer differ from this one?
Almost always because they count a different set of days. This page knows the federal holidays. It does not know your company’s shutdown week, a state or municipal holiday, a court’s own calendar or a carrier’s definition of a working day, and it cannot tell when a contract deadline is written in calendar days. When your rule differs, untick “Skip US federal holidays” to count plain weekdays.
Is a date before 2021 counted differently?
Yes. Juneteenth became a federal holiday when Public Law 117-17 was signed in June 2021, and this page does not apply it to earlier years, so a count spanning the 19th of June 2019 does not skip a day the country worked. The years 1986 to 2020 have ten federal holidays. The Birthday of Martin Luther King Jr. was first observed in 1986, so 1978 to 1985 have nine, and for years before 1978 the page removes no holidays.
Dates and Days