Everything on this page is plain calendar math, computed in your browser. A rotation is a repeating cycle of day shifts, night shifts, and days off, laid onto the real calendar of the year you pick. There are no estimates. You can check any cell against a wall calendar.
A night shift starts on its calendar day and ends the next morning. Two definitions follow from that. A full weekend off means no shift touches Saturday or Sunday, so a Friday night that ends Saturday morning costs you the weekend. A recovery day is the first day off after a night shift, because you spend its morning asleep.
The comparison chart averages each rotation over every starting position, since your place in the cycle changes how many weekends land in your off blocks. The download buttons render the charts exactly as drawn here, so anything you share can be reproduced on this page.
Both Saturday and Sunday have to be free, and no shift can touch them. A Friday night shift ends Saturday morning, so it disqualifies that weekend even though Saturday is technically a day off.
Where you sit in the rotation changes the answer. Rotations whose cycle length divides evenly into weeks, like Pitman (14 days) or DuPont (28 days), repeat on the same weekdays all year: one crew gets every other weekend off and another can get none. Rotations like 4 on 4 off drift through the week, so every crew ends up near the same average.
The first day off after a night shift. You spend its morning asleep, so it is not a usable day off. The visualizer counts these separately from true days off.
Among common rotations, 7 on 7 off days averages the most, followed by 4 on 4 off days. Night versions of the same patterns lose weekends to the Friday night rule. A fixed Monday to Friday schedule keeps all 52, which is the baseline everything else is measured against.
This page draws idealized patterns, and real rosters have swaps, overtime, and exceptions. Reading a real schedule is what the Lumical app does: photograph the roster and every shift lands in your calendar, overnights included. We make both, which is why this tool exists.
Every common rotation also has a standalone calendar page per year, with the full grid on real dates, annual hours, and a file you can import straight into your calendar.
Longer reads on how the common rotations actually behave over a year, written from the same calendar math as the visualizer.