Find out when you're most likely to ovulate, when your fertile window opens and closes, and where you are in your cycle right now. Whether you're trying to conceive or just curious about your body, here's what the numbers say.
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Ovulation typically happens about 14 days before your next period starts, not 14 days after your last one. This calculator works back from your expected next period to estimate your ovulation day and fertile window.
Your fertile window spans roughly the five days before ovulation plus ovulation day itself, because sperm can survive for several days. Calendar estimates are a starting point — ovulation timing varies, so signs like cervical mucus changes or ovulation tests give a more precise read.
This tool gives general information and estimates only — it is not medical advice. If you have concerns, speak to a healthcare professional.
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Explore the calculators →Usually around 14 days before your next period. In a 28-day cycle that's about day 14, but in a longer or shorter cycle it shifts accordingly — which is why counting back from your next period is more accurate than counting forward.
About six days: the five days leading up to ovulation plus ovulation day. This is because sperm can survive up to about five days, while the egg is viable for around 24 hours.
It's much less likely but not impossible, because ovulation timing can shift unexpectedly. Calendar estimates aren't precise enough to rely on for avoiding pregnancy.
Common signs include clear, stretchy cervical mucus, a slight rise in basal body temperature after ovulation, and mild one-sided twinges. Ovulation predictor kits detect the hormone surge that precedes it.