Ovulation calculator
Estimate the day you are most likely to ovulate and your fertile window, based on the first day of your last period and your average cycle length.
Frequently asked questions
How does the ovulation calculator work?
It estimates your ovulation day by counting back about 14 days from your next expected period, which is worked out from the first day of your last period plus your average cycle length. Your fertile window is the roughly six days ending on ovulation day.
When am I most likely to be fertile?
You are most likely to conceive during the fertile window — the five days before ovulation plus ovulation day itself. The two days before ovulation are usually the most fertile.
How accurate is the ovulation calculator?
It is an estimate based on an average 28-day cycle with a 14-day luteal phase. Real cycles vary between people and from month to month, so treat the result as a guide. It should never be used as a method of contraception.
Is the information I enter private?
Yes. The calculation runs entirely in your browser. Evecare never sees, stores, or transmits anything you enter.