It is possible to create an ovulation chart by tracking the timing of menstrual cycles for at least three consecutive months, as explained by WebMD. Ovulation typically occurs about halfway through the overall menstrual cycle.
The average menstrual cycle is between 28 and 32 days long, notes WebMD. Some women have shorter or longer cycles, or they experience cycles that are consistently irregular. To begin creating an ovulation chart, a woman should note the start and end date of her period. After doing this for a few cycles, she should start to see a pattern in the timing.
For ease of tracking, WebMD suggests treating the first day of a period as day one of a cycle. For a woman with an average cycle length, ovulation usually occurs between day 11 and day 21. Ovulation may occur along with increases in cervical mucus and basal body temperature, according to the American Pregnancy Association. Taking note of these two characteristics may help pinpoint the date of ovulation.
As of 2015, WebMD offers an online ovulation calendar that allows women to input information about their menstrual cycles. The user enters the starting dates of her last three periods to find her average cycle length. The program displays the next two calendar months with high-fertility dates and the expected date of her next period. Women tend to be most fertile between days 14 and 22 of a 28-day cycle.