Menstrual Cycle Tracker — Period & Ovulation Predictor Free Online
Track your menstrual cycle and predict your next period, fertile window, and ovulation day. View predictions on a visual calendar. Free, no sign-up, all data stays in your browser.
FAQ
Frequently asked questions about cycle tracker.
How does the cycle tracker predict my next period?
It adds your average cycle length (or the default 28 days) to the start date of your last period. The more cycles you log, the more accurate the average becomes.
When is the fertile window?
Ovulation typically occurs 14 days before the next expected period. The fertile window spans the 5 days before ovulation plus ovulation day itself, as sperm can survive up to 5 days in the reproductive tract.
Is this tool accurate for contraception?
No. Calendar-based methods are not reliable contraception, especially for irregular cycles. Consult a healthcare provider for contraceptive advice.
Is my data stored anywhere?
All data is processed entirely in your browser. Nothing is sent to a server or stored in any database.
What is a normal cycle length?
A typical menstrual cycle ranges from 21 to 35 days, with an average of 28 days. Period duration is usually 2–7 days. Both vary naturally from person to person and cycle to cycle.