When is ovulation?

First, we need to understand a woman’s menstrual cycle. Generally speaking, a woman's menstrual cycle lasts 28 days, but it varies from person to person. If your menstrual cycle is 28 days, your next cycle will be 30 days. Therefore, you can convert your cycle to 28 days/30 days for more accurate results.

So, if menstruation occurs on the 10th, the next cycle will be on January 10th, with a cycle of 28 days. After converting the 28 days/30 days, you get January 5th as the woman's next ovulation period.

Please note that this is just a simple calculation. In fact, women's menstrual cycle is affected by many factors, including genetics and living environment. Therefore, if your cycle is not 28 or 30 days, you may need to use other calculation methods to calculate ovulation.