Next period
Countdown and expected start based on your cycle length and last period.
16 days
until next expected period
Private cycle awareness
Know your rhythm, privately
Enter a few period details once. Luna shows your next expected period, fertile window, and lower-awareness days, all on this device.
- No account
- Local storage only
- Estimates, not medical advice
Today
At a glance
Day
12
of 28
Next period
16 days
Fertile windowLower awareness
What you get
Simple cycle signals
Built for quick checks on your phone or desktop, not a clinical tool.
Higher awareness
A roughly six-day band around estimated ovulation.
Local only
No login, no server sync. Cycle data stays in your browser.
How it works
Three steps, then you’re in
- 01
Open the app
Start from this page when you're ready. No signup wall.
- 02
Enter period details
Last start date, optional history, cycle and period length.
- 03
Check Today
See the full cycle timeline, next period, and a graded pregnancy-risk estimate in one place.
Estimates only
Luna uses calendar averages, not ovulation tests or medical data. It is not birth control and not medical advice. Cycles vary; when in doubt, talk to a clinician. Read how estimates work