Chronotype Planner

How does the planner compute the windows?

Each chronotype has fixed offsets in hours from your wake-up time. The peak window starts and ends at wake time plus those offsets: for the intermediate type, 3 to 6 hours after waking, so waking at 7:00 gives a peak window of 10:00 AM – 1:00 PM. The secondary and low-energy windows are built the same way.

Are these windows measured or scientifically derived?

They are the tool’s assumptions, written into the code as constants. Nothing here is measured from your own body clock, and the offsets are not drawn from a stated study. Treat them as a starting layout and move your work around according to when you actually feel alert.

What is a chronotype?

It is a person’s tendency to feel alert and sleepy earlier or later in the day. This tool offers five labels, from strong morning to strong evening, and you choose one yourself; it does not test you. If you are unsure, pick Intermediate.

Why does the recommended sleep time not change with my wake-up time?

It is a fixed value per chronotype: 9 PM for strong morning, 10 PM for moderate morning, 11 PM for intermediate, 12 AM for moderate evening and 1 AM for strong evening. Combined with a late or early wake time it can imply a very short or long night, so check the arithmetic against how much sleep you actually need.

What does the work-start input do?

It is used only for the “Peak window vs work start” line, which says how many of the peak hours fall before you start work. Otherwise the schedule depends on the chronotype and the wake-up time. A wake time with the peak before your start gives, for instance, “2.0 of 3.0 peak hrs fall before work starts” for a strong-morning type waking at 5 and starting at 9.

Why do some times end in :30?

The moderate-morning type uses half-hour offsets (2.5 to 5.5 hours after waking for the peak window), so waking at 7:00 gives 9:30 AM – 12:30 PM. The other types use whole-hour offsets.

Why is the “low energy” window earlier for evening types?

For the two evening types the low window is defined relative to waking: 3 to 5 hours after waking for moderate evening and 2 to 5 hours for strong evening. The tool labels it an “early morning slump”, even though a late riser’s window may fall around midday, as the sample with a 9:00 wake-up shows (11:00 AM – 2:00 PM).

What are the input limits?

Wake-up time is kept between 3 and 12, and work start between 5 and 14, as hours on a 24-hour clock. Values outside those ranges are moved to the nearest limit.