If your period comes on the 16th, the method for calculating ovulation is as follows:

A woman's menstrual cycle is affected by many factors, such as genetics, hormonal levels, and lifestyle. Therefore, accurately calculating a woman's menstrual cycle and determining her ovulation period is not a simple matter.

Generally speaking, a woman’s menstrual cycle can be divided into three phases:

1. The first seven days: The first seven days after the start of menstruation, this is called the safe period. Although the safe period is not absolutely safe, the probability of pregnancy during this period is relatively low.

2. The last seven days: The seven days after the end of menstruation are also called the safe period. The probability of pregnancy during this period is relatively low, but it is not absolutely safe.

3. Intermediate phase: The intermediate phase of the menstrual cycle, that is, from the eighth day to the twentieth day after the start of menstruation. The chance of pregnancy during this time is relatively low, but there are still risks.

Therefore, women who want to become pregnant need to understand their menstrual cycles and calculate their safe and dangerous periods. If a woman wants to have a baby, it's best to look for the best time in a woman's menstrual cycle to get pregnant.

In addition to calculating safe and dangerous periods, women can take other steps to reduce the risks of pregnancy. For example, women should take safety measures and avoid using condoms or other drugs during sex. In addition, women should maintain healthy eating and exercise habits to help improve body mass and improve women's menstrual cycles.

To summarize, calculating a woman's menstrual cycle and determining their safe and dangerous periods is very important for women who want to get pregnant. If a woman is unsure about her menstrual cycle or wants more information about menstrual cycles and pregnancy, talk to a doctor or professional counselor.