Repeating the exact cycle
Every preset is an ordered list of day, night, 24-hour duty, work, and off slots. Time Off Map stores calendar dates as date-only values so moving across a daylight-saving transition cannot accidentally skip or repeat a day.
The modulo operation works in both directions. That allows the calculator to generate dates before the known anchor as well as dates after it, including leap years.
Why one work date can still be ambiguous
A 24/48 schedule has one work position in its three-day cycle, so any known duty date identifies the phase. A 48/96 schedule has two adjacent duty positions. DuPont and rotating 2-2-3 schedules have many possible work positions.
Time Off Map therefore records both the known service date and the selected position in the visible cycle strip. It does not assume every work date is cycle day one. Users should verify several recent dates against the official roster before planning leave.
Finding a continuous bridge
The optimizer creates a chronological list of scheduled work shifts around the selected year. It tests consecutive groups of those shifts until their nominal PTO cost exceeds the entered budget. Every shift charged to PTO must begin within the selected calendar year, although the surrounding natural time off may cross a year boundary.
- Take the first selected PTO shift and locate the preceding work shift that remains scheduled.
- Take the last selected PTO shift and locate the next work shift that remains scheduled.
- Count every calendar date between those boundary shifts as uninterrupted time away.
- Record the PTO hours, natural off days, calendar days away, and return-to-work date.
Longest sorts by total days away. Best value sorts by PTO leverage. Soonest sorts by the first date of the break. Ties favor the longer break, lower cost, then earlier date.
Informational unless you say otherwise
Shift operations commonly continue through public holidays. Federal holidays are therefore marked but remain scheduled work by default. Turning on “Treat U.S. federal holidays as off” removes an otherwise-scheduled shift on the observed federal date from PTO cost.
The built-in dates include New Year’s Day, Martin Luther King Jr. Day, Washington’s Birthday, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving, and Christmas, including standard Friday or Monday observance for fixed-date holidays. Employer holidays and in-lieu days can differ.
Service dates and nominal PTO hours
A shift belongs to the local calendar date on which it begins. The current calendar export represents work as an all-day event on that service date. This avoids inventing a time zone or relief time that the user has not provided.
Nominal PTO hours are separate from elapsed clock time. A 24-hour shift crossing a spring daylight-saving change may contain 23 elapsed hours, while an employer may still charge 24 leave hours. Time Off Map currently uses the nominal hours shown in the preset.
What version 1.0 does not model
- Partial-shift PTO or employer-specific leave increments
- Shift trades, mandatory overtime, training, callbacks, or temporary roster exceptions
- Existing approved leave and blackout dates
- Department-specific Kelly, debit, relief, or union rules outside the selected preset
- Multiple non-overlapping vacations optimized as one annual portfolio
- Overtime, payroll, FLSA, or legal-compliance determinations
Time Off Map is a planning aid, not an official roster, payroll system, or promise of leave approval.