Two ways to count working days
The first mode counts business days between two dates. Both the start and end date are included, and Saturdays and Sundays are removed. A full calendar year contains about 261 weekdays, and after the eleven federal holidays roughly 250 business days remain. As a worked example, from Monday June 1, 2026 through Friday June 12, 2026 there are 12 calendar days, of which 2 fall on the weekend of June 6 and 7; no federal holiday falls in that window, so the answer is 10 business days.
The second mode moves a number of business days forward or backward from a start date. The start date itself is never counted, which matches how contracts and court rules read: ten business days from Friday, March 6, 2026 lands on Friday, March 20, 2026, two calendar weeks later, because no holiday interferes. Enter a negative number to count backward, which is how you find the last day to file something a set number of working days before a deadline.
How the federal holidays are computed
Holidays are calculated by rule for any year rather than read from a fixed list, so the tool works decades into the past or future. Four fall on fixed dates: New Year's Day on January 1, Juneteenth on June 19, Independence Day on July 4, Veterans Day on November 11 and Christmas on December 25. The rest are floating Mondays and one Thursday: Martin Luther King Jr. Day is the third Monday in January, Presidents Day the third Monday in February, Memorial Day the last Monday in May, Labor Day the first Monday in September, Columbus Day the second Monday in October and Thanksgiving the fourth Thursday in November.
Federal offices follow an observed rule for the fixed-date holidays. When one falls on a Saturday it is observed on the preceding Friday, and when it falls on a Sunday it is observed on the following Monday. July 4, 2026 is a Saturday, so the federal holiday is observed on Friday July 3. The results table marks these with the word observed so you can see exactly which weekday was removed.
Where the definition varies
Federal holidays bind federal agencies and the bond markets, but private employers set their own calendars. Many banks close on Columbus Day while most retailers do not, and state holidays such as Patriots' Day in Massachusetts or Cesar Chavez Day in California are not in this list. Court deadlines often have their own rules, including counting rules that extend a period landing on a weekend to the next business day. When a number of business days appears in a contract, check whether the agreement defines the term, and turn the holiday option off if only weekends should be removed.