Loading...
Loading...
Predict your next period dates and ovulation window based on your cycle history.
This period/ovulation calculator estimates dates based on the information you provide. It does not guarantee pregnancy, fertility, ovulation timing, or menstrual cycle accuracy and should not be used as birth control.
Next Period = Last Period Start + Cycle Length. Ovulation ≈ Next Period - 14 days.
Result: Next: Jan 29 - Feb 2, Ovulation: Jan 15
Accuracy depends on cycle regularity. Irregular cycles make prediction less reliable.
Cycle lengths of 21-35 days are considered normal. 28 days is the average.
Track your cycle for 3-6 months to find your average cycle length. Irregular cycles over 35 or under 21 days may warrant a consultation with a healthcare provider.
Hormonal contraceptives like birth control pills create a controlled cycle, making period prediction very accurate since the timing is regulated by the medication rather than natural cycles.