Private offline period tracker
No account, AI or record uploads. The independent app has no ads or analytics.
Recording happens in a separate offline-ready page, not in this tool form.
This password never leaves your browser. It cannot be reset. Backups need the same password. The notebook locks after 10 minutes of inactivity.
Center: median of up to 6 recent intervals. Range: shortest to longest observed interval, not a statistical confidence interval. Future cycles can fall outside it.
Turn off estimates during pregnancy, postpartum, breastfeeding, hormonal contraception or when calendar assumptions do not apply. Fertility reference assumes ovulation 14 days before the estimated center, plus the preceding 5 days; it does not confirm ovulation.
Calendar estimates cannot detect ovulation, pregnancy or illness. Never use them for contraception. For severe pain, unusually heavy bleeding or concerning changes, seek medical advice.
Clearing site data, private browsing or browser cleanup can erase records. This device/browser has its own notebook; there is no cloud sync.
Encrypted at rest, not an anonymity guarantee. An unlocked screen, malicious extension, compromised device or compromised site code can expose records. The initial app download still contacts this website.