Ovulation Calculator

Knowing when you are most likely for to be fertile can help increase your chances of getting pregnant. A typical menstrual cycle lasts 28 days, but every woman is different. You can become pregnant on average 6 days per menstrual cycle. This is your fertile window. The calculator will show you which days are most fertile.

Ovulation Calculator
When did your last period start?
E.g. 18/01/2020
Usually, how long is your cycle?
Cycles typically vary from 23 to 35 days
Estimate your ovulation day
likelihood of ovulating today
Due to your cycle length, unfortunately we can’t estimate an ovulation probability. We recommend that you use a Digital Ovulation Test to accurately detect your most fertile days.
  *
Start of your last period
  20%
Likelihood of ovulating on this date
Change my information
In partnership with Clearblue®.
Results are based on the information you have provided and data from the publication below: Sarah Johnson, Lorrae Marriott & Michael Zinaman (2018): “Can apps and calendar methods predict ovulation with accuracy?”, Current Medical Research and Opinion, DOI:10.1080/03007995.2018.1475348

This calculator calculates your fertile window. It does not guarantee pregnancy. This website and the calculator are not intended to be used as medical advice. Talk to your doctor to discuss pregnancy planning and to find the best birth control for you.

Every woman’s fertility window is different and can vary from one month to the next. If you’re trying to get pregnant, learn more about your fertility.

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