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Cycle length planner
Enter a start date, an interval in days, and how many entries or weeks you want to project. The planner lists the actual dates and shows how an every-N-day schedule drifts across weekdays — which is precisely what weekday-checkbox trackers cannot represent.
Why intervals drift
Seven divides the week; nothing else useful does. An every-3-day schedule starting on Monday lands on Thursday, Sunday, Wednesday, Saturday and onward, never settling. That is not a problem to be fixed — it is what the interval means — but it does make the schedule hard to hold in your head, and impossible to express as a set of weekday checkboxes.
See every-N-day schedules for why so many trackers cannot represent this, and what anchoring does when an entry is late.
Using the projection
- Check it against your calendar before committing — an interval that lands on every travel day is worth knowing about in advance.
- Cross-reference vial duration so you can see whether the schedule outlives the vial. Use the vial duration calculator.
- Note the on/off transitions if you are cycling, since those are the dates people actually miss.
- Record the plan in your log, so later divergence from it is visible rather than invisible.
Frequently asked questions
Why does my every-3-day schedule keep moving?
Because three does not divide seven. Any interval other than seven days drifts across weekdays continuously, which is inherent to interval-based scheduling rather than an error.
How do I plan an on/off cycle?
Specify a cycle length — a number of days or weeks on, followed by a defined break — plus a start date, and project it forward. Recording it as a shape rather than a list of dates means the calendar can extend it indefinitely.
Can two compounds run on different intervals?
Yes, and it is common. Each compound needs its own schedule, which produces overlapping rhythms on one calendar. Forcing both onto a single interval makes the record wrong for at least one of them.
Related pages
Stop recalculating this every time
PepCycle stores each vial once — mass, diluent volume, concentration — and converts automatically for every entry after that, in both directions, including entries you backdate.
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