The method for calculating ovulation is as follows:

To determine ovulation, you need to know a woman's menstrual cycle and cycle length. If a woman's menstrual cycle is 28 days, then their cycle length is usually 28 days. If women have different cycle lengths, then ovulation needs to be determined on a case-by-case basis.

In addition, women can determine their ovulation period through the following methods:

1. Observe sexual desire: During ovulation, a woman’s sexual desire will increase and she may feel more excited and sensitive.

2. Observe basal body temperature: Women can determine the ovulation period by measuring basal body temperature. Basal body temperature is the body temperature a woman takes each morning when she wakes up, and it usually changes during a woman's menstrual cycle. During ovulation, a woman's body temperature will rise by 0.3 to 0.5 degrees Celsius.

3. Observe symptoms: During ovulation, women may feel pain on one side of their abdomen, which may be a symbol of egg release. Additionally, women may experience breast tenderness and nipple sensitivity.

4. Use a calendar: Women can use a calendar to determine when they are ovulating. Mark a woman's menstrual cycle and cycle length on a calendar, and use the time on the calendar to determine ovulation.

The above methods can only be used as a reference, because everyone's physiological situation is different, so the specific calculation method may be different. If women want to determine the exact date of ovulation, it is recommended to consult a doctor or a professional health care provider.