Online ovulation period is a convenient and fast method that can help women better control their fertility cycle. Although online ovulation calculation is not as accurate as traditional laboratory measurements, it is still a useful tool that can help women better plan their fertility.

The female menstrual cycle usually consists of three parts: the ovarian cycle, the uterine cycle, and the vaginal cycle. The ovarian cycle refers to the process by which a woman's ovaries produce eggs, which usually occurs around day 28 of the menstrual cycle. The uterine cycle refers to the process of a woman's uterus contracting and releasing an egg, which usually occurs around day 14 of the menstrual cycle. The vaginal cycle refers to changes in a woman’s vaginal secretions, which usually occur around days 7-10 of the menstrual cycle.

The steps to calculate ovulation online are as follows:

1. Record basal body temperature: Women need to measure their basal body temperature every day when they wake up in the morning.

2. Calculate the body temperature change cycle: Women need to divide the recorded basal body temperature data by 2 to calculate the body temperature change cycle.

3. Determine the ovulation period: Women need to determine their ovulation period based on the body temperature change cycle. On the last day of the body temperature cycle, a woman's body temperature usually rises by 0.3-0.5 degrees Celsius, which is generally considered to be the woman's ovulation period.

4. Arrange a birth plan: Women can arrange their own birth plan according to their body temperature change cycle and ovulation period. During the ovulation period, women can increase their chances of having children, but they also need to pay attention to safety measures to avoid pregnancy.

Although online ovulation calculation is not as accurate as traditional laboratory measurements, it is still a useful tool that can help women better plan their fertility. Women can infer their ovulation period by recording their basal body temperature data and comparing it at different times during the cycle.