Estimate your ovulation day, fertile window, next period and due date from your last period and cycle length.
Likely ovulation day
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The next six cycles
| Period starts | Fertile window | Ovulation |
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Already pregnant? Find your due date and week by week with the due date calculator.
In the five days before ovulation and on the day itself. Sperm can live for up to five days, and an egg for about a day, so the two or three days before ovulation give the best chance of pregnancy.
Ovulation usually happens about 14 days before your next period starts. With a 28-day cycle that's day 14; with a 32-day cycle, day 18. The calculator counts from the first day of your last period and your usual cycle length.
It's an estimate based on regular cycles. Ovulation can move from month to month with stress, illness or travel. Ovulation test kits, cervical mucus and basal body temperature give a more exact picture.
No. Calendar methods alone are not reliable birth control. Talk to a doctor or a family planning clinic about contraception.
