Track your cycle
Log your periods and see predictions for your next period, ovulation day, and fertility window, so you always know what’s coming and can plan ahead.
Your period, your data.
Track your menstrual cycle without giving up your privacy.
No account required
All data stays on your device
No ads or third‑party trackers
Open source
Stay in tune with your cycle, privately
Symptoms and mood tracking
Track your symptoms, mood, flow intensity, and other health markers.
Cycle statistics
Get a full picture of your cycle, and view your cycle history.
PIN lock protection
Add an extra layer of privacy with a 4-digit PIN lock or Face ID/Touch ID.
Data deletion
Delete your data anytime, instantly.
Dark mode
Reduce eye strain and save battery with system‑aware dark mode.
Why choose Lunari?
Privacy‑first by design
Built from the ground up to store your data locally on your device.
On-device predictions
Predictions are computed on‑device from your cycle history, no cloud needed.
Open source
Lunari is open source, you can see the code on GitHub.
How predictions work
Next period prediction
Lunari predicts your next period by adding your average cycle length to the start date of your last period.
Cycle average length calculation
Lunari calculates your average cycle length using a weighted average of your last 6 cycles, a commonly used approach in cycle tracking.
Recent cycles have more influence on predictions than older ones. For example, most recent cycle: 100%, second most recent: 80%, third most recent: 60%, and so on.
More data, better accuracy
Track at least 3 cycles for basic predictions. After 6 cycles, predictions are more accurate.
IMPORTANT: Predictions are estimates based on your tracking history, not medical advice. See a healthcare provider if you have concerns.