Women’s cycles can vary and are not always as regular as clockwork, so to know that you are ovulating and on which day of your cycle you are ovulating, observe your fertility signs throughout your cycle and record them on a chart.
The most accurate methods of working out when ovulation is about to occur are:
Keep an eye out for changes in your mucus. Around the time of ovulation, you may notice your vagina’s mucus is clear, slick and slippery, the consistency of egg white. This is the best sign of when ovulation is actually happening. It’s prime time for action.
Use an ovulation predictor kit. You can start testing with your ovulation predictor kit a few days before your estimated day of ovulation. Subtract 17 days from your average cycle length and start testing from this day of your cycle, e.g. if you have a 28 day cycle, you would start testing from day 11. A positive result means you are going to ovulate within the next 24 to 36 hours.
Record your basal body temperature (BBT) each day before getting out of bed. A special basal body temperature thermometer will ensure accurate measurement. Your BBT rises about half a degree Celsius after ovulation has occurred. By charting your temperature, it’s easy to see when the rise in temperature and ovulation happens. This can help you work out your own pattern of ovulation. However, because at that stage ovulation has already passed, it does not help you pinpoint the fertile window but may guide you for next month.
Use the ovulation calculator on this site. If you know the date of your last period, the length of your cycle and your cycle is regular, this will identify your ‘fertile window’ and predicted ovulation date.