Predict your next 6 period dates based on your cycle. Know when to expect your period, plan around it, and track your cycle over time.
A typical menstrual cycle ranges from 21 to 35 days, with 28 days being the average. "Regular" means your cycle length is consistent from month to month — it doesn't have to be exactly 28 days. Cycles that vary by more than a week are considered irregular and may be worth discussing with a doctor.
The most common causes of a late period (besides pregnancy) include stress, significant weight change, excessive exercise, illness, hormonal changes, thyroid issues, polycystic ovary syndrome (PCOS), and perimenopause. Occasional late periods are normal; consistently irregular cycles warrant a conversation with your healthcare provider.
This calculator assumes a consistent cycle length. The prediction is most accurate for people with regular cycles. If your cycle varies by several days each month, the actual date may differ from the prediction. Tracking your actual period start dates over several months will improve accuracy.