Sleep around your rota

How the planner lays out the sleep

Every block is whole cycles, and every one either starts or ends at a time the rota fixes. There are four rules, and they are the whole of the planner:

• After a shift that finishes in the morning, a block starts as soon as you are home and have had your time before bed. It is the full count when the next shift is that same evening, and the switch count when a day off comes next.
• Before a shift that starts in the morning, a block ends when you have to be up for it: the start, less the commute, less the time to get ready.
• On any morning that is not a shift morning, a block ends at the time you get up on a day off.
• Before a night shift that follows an ordinary night, a top-up of the switch count ends when you have to be up for the shift.

A block that will not fit before the next thing in the day loses a cycle at a time until it does, and the table says how many it lost. A gap too short for even one cycle is marked. Those two marks are the only judgement on the page, and they are the arithmetic's.

The switch days

In the 2-2-4 rota the planner opens on, the second day shift ends at 6:00 pm. The next morning is not a shift morning, so that night runs to the usual wake time, 11:15 pm to 7:00 am, and the first night shift gets a top-up of 2 cycles, 1:15 pm to 4:30 pm, ending when you have to be up for it.

Between the two nights, the block after the shift is the full count: 7:00 am to 2:45 pm, 7 and a half hours asleep. Coming off the second night, with a day off next, it is the switch count, 7:00 am to 10:15 am, and that night runs to the usual wake time again.

The switch count starts at 2 because a planner has to start somewhere, not because two is right. Set it to nought and the top-up and the short sleep both disappear; set it to four and they become most of a night. Which of those suits a person, a household or a ward is not a number this site has.

The patterns on the menu

Each is a starting point you can type over. The first four take their cells and hours from the worked examples in the shift plan article; the last two are simpler patterns, set out below. A workplace's own rota always wins.

• 2-2-4 is two twelve-hour days, two twelve-hour nights and four days off, 8 days in all, on the hours the article gives: 6:00 am to 6:00 pm, and 6:00 pm to 6:00 am.
• 4-on-4-off is four twelve-hour shifts and four days off. The article's example runs from 7:00 am to 7:00 pm; the preset is four days, and four nights is a change of letter.
• Pitman, or 2-2-3, is a fortnight of twelve-hour shifts: two on, two off, three on, two off, two on, three off. The article calls it the Panama plan and notes that it is not uncommon for crews to rotate between days and nights, so the preset is a fortnight of days, and N in place of each D makes it a fortnight of nights.
• DuPont runs 28 days: four nights, three off, three days, one off, three nights, three off, four days and seven off, twelve hours a shift. It is crew A of the article's four-week example.
• 3×12 is three twelve-hour shifts in a week. The preset puts them on the first three days; move the letters to spread them out.
• 24/48 is twenty-four hours on and forty-eight off, a 3-day cycle, the pattern the article describes for fire services. The preset starts the shift at 7:00 am, which is a starting value; change it to your own. Whatever sleep a shift that long allows on duty is not a number the planner has, so none is laid inside it.

Longer rotas are typed the same way, up to 28 days. The day and night hours apply to every D and every N; a rota with a third kind of shift is two rotas as far as this planner is concerned.

The calendar file

The download is an iCalendar file, the format calendar apps import, made in your browser from the table: one event for each block of sleep, from the day you choose as day 1, for the number of weeks you choose. Nothing is sent anywhere to make it, and the site never sees it.

The times in it are floating. The iCalendar standard, RFC 5545, defines a date and time with no time zone as "the same hour, minute, and second value regardless of which time zone is currently being observed", which is how a rota is written. It also means the file knows nothing about the nights the clocks change: a block that runs through the change still shows its printed times, and holds an hour more or less than it says.

One shift at a time

Five common shifts have a page of their own, each with the same sums for that shift repeated and a section on when its hours fall in daylight in London, New York, Johannesburg, Cape Town and Sydney through the year.

The five side by side

At the planner's defaults: an hour between clocking off and getting into bed, fifteen minutes to drop off, cycles of ninety minutes, and an hour and a half between getting up and starting the next shift. The next shift is taken to start at the same time the following day, as it does in a run of the same shift; before a day off or a change of rota the time until it starts is longer than the table shows.

The three eight-hour rotas leave the same seven and a quarter hours after five cycles, and the two twelve-hour rotas the same three and a quarter, because what is left depends only on the length of the gap between shifts and not on where the gap falls on the clock. Split three and two, the eight-hour rotas leave five and a half hours awake between the blocks and the twelve-hour rotas an hour and a half.

Where the gap falls is what separates them, and it is what each shift's own page is about: which of those hours are daylight in the five cities through the year, and what the nights the clocks change do to the shift and to the sleep around it. If your hours are not one of the five, open whichever is nearest and type your own into the two fields at the top.

Why the rows are cycles rather than hours

For the same reason they are everywhere else here: a shift leaves you a fixed gap, and the question is how many whole cycles fit in it rather than how many hours. The reasoning is set out in counting cycles, not hours, and it applies to a gap between two shifts exactly as it applies to a night.

What this page is not doing

It is not saying which rota is better, when to see daylight, what to drink or what to take, because it has measured nobody and cannot know. It lays whole cycles between the times a rota fixes and adds them up. What an arrangement is worth is a question about your life, your work and your household, and none of those are numbers this site has.