Period Calculator
About Period Calculator
Understanding Your Menstrual Cycle
The menstrual cycle is the monthly process your body goes through to prepare for a possible pregnancy. A typical cycle lasts 21-35 days, with 28 days being the average. The cycle consists of four phases: menstruation (days 1-5), the follicular phase (days 1-13), ovulation (around day 14), and the luteal phase (days 15-28). Tracking your cycle helps you understand your body's patterns, predict upcoming periods, identify irregularities that may warrant medical attention, and plan for activities around your period.
How Period Prediction Works
This calculator predicts your next period by adding your average cycle length to the start date of your last period. For better accuracy, it can use the average of your last few cycle lengths if you provide them. The prediction assumes regular cycles. If your cycles are highly irregular (varying by more than 7 days), predictions become less reliable and you should consult a healthcare provider.
How to Use This Calculator
Enter the start date of your last period and your average cycle length. The calculator displays predicted dates for your next 6 periods, expected period duration, and the phases of each upcoming cycle. It also indicates PMS window (typically 1-2 weeks before period) and safe vs fertile days based on your cycle pattern.
Frequently Asked Questions
What is a normal cycle length?
Normal cycles range from 21 to 35 days for adults. Cycles shorter than 21 or longer than 35 days may indicate hormonal imbalances and should be discussed with a doctor.
Why is my period irregular?
Common causes include stress, significant weight changes, excessive exercise, polycystic ovary syndrome (PCOS), thyroid disorders, and hormonal contraception changes. Occasional irregularity is normal, but persistent irregularity warrants evaluation.
How can I make predictions more accurate?
Track your cycle for at least 3-6 months to establish your true average. The more data points you have, the more accurate predictions become. Irregular cycles require more data for reliable predictions.
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