Why business days need a page and calendar days do not
A calendar-day answer is arithmetic. A business-day answer is arithmetic plus two policy decisions: which days count as a weekend, and which holidays close an office. Get either wrong and the answer is wrong by days, not hours — which is why a search engine will happily answer "30 days from today" in a box and will not answer "30 business days from today".
Ours uses Monday to Friday, and the eleven US federal holidays on the dates they are observed — so a holiday falling on a Saturday is skipped on the Friday before, because that is the day the office is shut. State, bank and court holidays are not included; they vary by jurisdiction and picking one would be wrong for most visitors.
What each page tells you
The resulting date and weekday, the calendar-day equivalent, how many weekend days were stepped over, and every holiday it skipped, by name and date. That last one is the point: if the count crossed Thanksgiving and Christmas, you can see it did, and check it.
Ten business days is two working weeks and the most common turnaround commitment in US administrative process; twenty appears in records statutes and appeal windows; 250 is roughly a working year. If you need to count from a date other than today, or backwards, use the business days calculator, and see where our holiday dates come from for the full list.