Predict your next period, track your menstrual cycle, and see a full fertility calendar. 100% private — all calculations happen in your browser.
The menstrual cycle is the monthly series of changes a woman's body goes through in preparation for the possibility of pregnancy. This calculator predicts your next period dates, ovulation day, and fertile window based on your last period and average cycle length. The typical cycle is 28 days, but anything from 21 to 35 days is considered normal. Every body is different, and this tool provides estimates for planning and tracking purposes.
This calculator provides estimates based on average cycle patterns. Actual cycles can vary due to stress, illness, travel, hormonal changes, and other factors. For the most accurate tracking, consider recording your cycles over several months.
A normal menstrual cycle ranges from 21 to 35 days, with 28 days being the average. If your cycle is consistently shorter than 21 days or longer than 35 days, consult a healthcare provider.
Your fertile window is typically 5-6 days: the 4 days before ovulation, the day of ovulation, and the day after. Ovulation usually occurs about 14 days before your next period starts.
Yes. All calculations happen entirely in your browser. No personal data is sent to any server, stored, or shared.