CountBusinessDays uses the official list of U.S. Federal holidays as defined by the Office of Personnel Management (OPM), including observed dates when a holiday falls on a weekend.
| Holiday | Date Rule |
|---|---|
| New Year’s Day | January 1 |
| Martin Luther King Jr. Day | Third Monday in January |
| Washington’s Birthday (Presidents’ Day) | Third Monday in February |
| Memorial Day | Last Monday in May |
| Juneteenth National Independence Day | June 19 |
| Independence Day | July 4 |
| Labor Day | First Monday in September |
| Columbus Day | Second Monday in October |
| Veterans Day | November 11 |
| Thanksgiving Day | Fourth Thursday in November |
| Christmas Day | December 25 |
When a fixed-date holiday falls on a weekend, the following observed rules are applied:
These observed dates are the ones used in all business-day calculations.