Three steps.
- 1Log your period
Tap the day it started. The loop, the month and the next date follow from your own dates, not from an average of strangers.
- 2See it on your day
Today shows the day of your cycle and its phase, and the month view paints your periods, the fertile window and ovulation.
- 3Plan with it
On a lower-energy phase your day is measured as lighter, and one tap asks the planner to move what can move.
Your cycle
Ovulation in
6 days
Day 9 of 28
Next period
31 Oct
Fertile window
12 – 17 Oct
Ovulation
17 Oct
Energy
Rising
Your cycle, on your day.
What it does for you.
A loop, not a log
Your cycle as one ring of four phases, with a countdown to ovulation or to your next period in the middle.
Your month, painted
Logged periods solid, expected ones soft, the fertile window as a band and ovulation as a dot. Past months show what really happened.
It learns your length
Once two starts are logged, the length follows your own average. A month you forgot to log is left out instead of stretching it.
Private by design
Never sent to OpenAI or anyone else, never shown to your circles, and gone in one tap when you delete it.
More than one kind of cycle
Rhythm repeats any cycle of phases: a menstrual cycle, a training block of build, push, peak and deload, a shift rotation, or a work sprint. Each kind keeps its own dates, so trying another and coming back costs nothing you logged.
Where it runs
Rhythm is in TimeLoop for iPhone and Android today, and kept on the phone. With the next update it is kept with your account, encrypted, so the same cycle is on every phone you sign in on, in TimeLoop in the browser and in TimeLoop for Mac, which is coming. Periods already kept in your phone’s health app can then come in by themselves, if you switch it on; logging by hand stays complete on its own.
What it costs
Rhythm is free. Planning your day from a sentence, the measured way to each place and the other things that do the work for you are part of TimeLoop Pro.
What it is not
Ovulation and the fertile window are calendar estimates from your own dates. Rhythm is not a medical or contraceptive tool, and it does not diagnose anything.
Asked before you asked.
Is there a planner that follows my cycle?
Yes. TimeLoop’s Rhythm shows your menstrual cycle on your day, with today’s phase, your next period and the fertile window, and plans a lighter day on a low-energy phase. It is free.
How does it know when my next period is due?
It counts from the starts you log. Once two are logged, the length follows your own average, and a period that comes early or late moves the next date with it.
Is my cycle private?
Yes. It is never sent to OpenAI or anyone else and never shown to your circles. Today it stays on your phone; with the next update it is kept with your account, encrypted, so it is the same on every device you sign in on. Deleting rhythm data removes it everywhere.
Is it a contraceptive?
No. Ovulation and the fertile window are calendar estimates, not a medical or contraceptive tool.
Can I use it for training or shift work?
Yes. Choose a training block, a shift rotation or a work sprint instead, and each keeps its own dates.
Some days you have less in you than the plan assumes. TimeLoop asks how you feel, once a day, and when today holds more than that, it offers to move the heaviest things that can wait.
Read Focus timerFocus timerPick what you are working on, from the event that is running or your tasks, set how long, and the TimeLoop ring runs down while the steps sit beside it. In the browser now, on iPhone with the next update.
Read For studentsStudentsWriting “study for the exam” on a list does not make the hours appear. Tell TimeLoop how many you need and by when, and it puts them between your classes.
ReadLast updated 16 October 2026.