In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser.

Ovulation Calculator

Use this tool to help you calculate the best time to get pregnant by identifying your ‘fertile window’ each month.

Your ‘fertile window’ is the time during a month when sperm in the fallopian tubes are most likely to meet an egg released from the ovary. This is usually from about two to three days before ovulation to when the egg has travelled down to the uterus. Having sex without using contraception at this time may increase your chances of conceiving.


You will need the dates of your recent menstrual periods to identify the first day of your last period and your usual cycle length.

Your cycle length is the number of days between the first day of bleeding of one period and the first day of bleeding of your next period. This tends to vary from 23 to 35 days with the average being a 28 day cycle. If you have irregular menstrual cycles, or your cycle length varies from month to month, it may be difficult to calculate your ovulation date. In this case, use your shortest period date. It is important to start earlier to ensure your ovulation date is not missed.

If you have any questions about ovulation tracking or your fertility window consider seeking further advice from your GP or fertility specialist.

This calculator has been provided by the Queensland Fertility Group and reviewed by Bupa health professionals. It is based on reputable sources of medical research. It is not a diagnostic tool but is a guide only and should not be relied on as a substitute for professional medical or other professional health advice.