Weekends come out, US federal holidays come out, and the page lists exactly which days it removed — so you can check the number rather than trust it.
Which reading of "days between" you want
Two people asking how many days lie between the 1st and the 8th can reasonably want different answers. Seven is the gap: the number of nights, the number you add to one date to reach the other. Eight is the count of dates involved, which is what the question means when it is really "how long is my trip" and both ends are days you are somewhere.
This page defaults to the gap and offers the other with a checkbox, and the sentence under the answer always names which one it used. A calculator that quietly picks one is right half the time and never tells you which half.
Why the arithmetic runs in whole days
A date here is a year, a month and a day, not a moment in time. 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. The one place local time is used is the word "today", because that is a question about where you are standing. The how the observed-date rule is applied sets out the rules in full.
Working days instead of calendar days
If the count you need has weekends and public holidays taken out — the shape most shipping windows and legal deadlines use — the business days calculator does that, and lists every day it removed so you can check it rather than trust it.
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 differ by a day, which is usually the whole question, so the line under 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. Every one is computed from the rule in 5 U.S.C. 6103 rather than read from a list, so it stays correct in years nobody has typed in yet.
What happens when a holiday falls on a Saturday or Sunday?
The day the country actually closes is the day that comes out. 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. One case is easy to get wrong and this page handles it: 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 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. It also does not know a deadline written in a contract that counts calendar days rather than business days. When your rule differs, untick the holidays box to get plain weekday counting, which is simple and correct, rather than an elaborate answer that is wrong.
Is a date before 2021 counted differently?
Yes, and deliberately. Juneteenth became a federal holiday when Public Law 117-17 was signed in June 2021, so a year before that has ten federal holidays rather than eleven. A count spanning the 19th of June 2019 must not skip a day the country worked, so this page does not apply the holiday to years that predate the statute.
Dates and Days