PetalLog your period in 3 seconds
A period calendar with no account and no server — for your eyes only
One tap logs your period. Weighted predictions adapt when your cycle shifts, so your next period, ovulation day, and fertile window stay accurate on the calendar. Everything is stored only on your phone.
Sound familiar?
Period apps demand a sign-up, and you have no idea where your body data goes
"When was your last period?" — the doctor asks, and you never remember
Bloated apps with ads and social feeds make you not want to open them at all
Petal keeps it quiet, simple, and private
Cycle tracking, simpler and more private
Only the essentials — and only on your phone
3-second logging
One button on the home screen logs your period start and end. With the widget, you don't even need to open the app.
Predictions that follow your cycle
Recent cycles are weighted more heavily, so when your cycle gets longer or shorter, predictions adapt with it.
Ovulation & fertile window calendar
Period, predicted, fertile, and ovulation days are color-coded on one calendar — with today's pregnancy chance up front.
Goal modes
Choose track, conceive, or avoid — your daily status message adjusts to what matters to you.
Symptoms, mood, intimacy & pill
Log symptoms, moods, intimacy, and contraceptive pills in a few taps. Cycle history shows your patterns over time.
100% on-device storage
No account, no server. Everything lives only on your phone, with JSON export/import for backup. Delete the app and the data is gone too.
See it in action
From logging to predictions in a few taps
Know your next period at a glance
Period, fertile & ovulation days in color
Average cycle and your next three predictions
Symptoms, mood & pill — logged in 3 seconds
Getting started is this simple
Install and start right away
No sign-up. Just tell Petal when your last period started and you're set.
One tap when your period starts
Tap once when it starts. Add symptoms or moods only when you feel like it.
Petal handles the predictions
The more you log, the smarter your next-period, ovulation, and fertile-window predictions get.
Frequently asked questions
Is it really free?
Yes. Petal is free to download and all core features are free to use.
Where is my period data stored?
Everything is stored only on your phone. There's no account and no server, so your data never leaves your device — and deleting the app deletes the data. Moving to a new phone? Use JSON export/import.
How accurate are the predictions?
Petal predicts your next period with a weighted average that favors recent cycles, so predictions follow along as your cycle shifts. Calendar-based estimates are for reference only — for contraception or conception decisions, consult a healthcare professional.
Does it show ovulation and fertile days?
Yes. The calendar color-codes your estimated ovulation day and fertile window, and the home screen shows today's pregnancy-chance status. Guidance adapts to your goal mode: track, conceive, or avoid.
What if someone sees my notifications?
Notifications use discreet wording that doesn't reveal their content. Both period reminders and pill reminders can be turned on or off any time.
Is there an iOS (iPhone) version?
Petal is currently Android-only. An iOS version is under consideration.
A period calendar only you can see
Install without signing up and make your first 3-second log today