Enter the first day of your last period and your usual cycle length to see an estimated ovulation date, fertile window and next period.
We use the standard calendar method: ovulation is estimated to occur a number of days before your next period equal to your luteal phase length (commonly 14 days), counted forward from the first day of your last period. The fertile window covers the roughly five days before estimated ovulation plus ovulation day itself, since sperm can survive several days and the egg is viable for about a day.
Cycle length varies naturally from month to month, and ovulation timing shifts with stress, illness, travel, sleep disruption, significant weight change and some medications. This calculator assumes a textbook-average cycle; your own cycle may differ, especially if your cycle length itself varies a lot.
No. Calendar-based estimates like this one are not accurate enough to rely on for contraception or for timing conception with confidence. If either is your goal, use a clinically validated method (such as basal body temperature combined with ovulation predictor kits) or speak with a doctor or gynecologist.
Quantum Khor is a wellness companion, not a medical device. It does not diagnose, treat or prevent any condition.