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Ovulation Calculator

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The length of your cycle can vary every month. An ovulation calculator* can help to determine your cycle’s length by counting the days from the first day of your period up to, but not including, the first day of your next period. The average woman’s menstrual cycle lasts about 28 days but it is perfectly normal for a cycle to last anywhere from 24 to 34 days.

On average, ovulation occurs 14 days before the start of your period. However, it is normal for a woman to ovulate anywhere from 12 to 18 days before menstruation. When trying to fall pregnant it can be helpful to keep a record of your menstrual cycle and ovulation calendar.

An ovulation calculator will give you an indication of your fertility window based on the length of your cycle. Please remember that ovulation calculators are just a guide and to determine your precise ovulation date, we recommend talking to one of our Fertility Doctors or booking a free Nurse Chat.

How to calculate ovulation:
Work out the length of your menstrual cycle by counting the days from the first day of your period up to, but not including, the first day of your next period.

Once you know how many days your shortest cycle is (eg. 28 days) and how many days your longest cycle is (eg. 30 days) then subtract 14 from these numbers

28 – 14 = 14  and  30 – 14 = 16

The earliest you are likely to ovulate is on day 14 and the latest you are likely to ovulate is on day 16 of your cycle.


*there are many freely available on-line calculators or as downloadable apps for your smart phone.

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