There are many ways to calculate ovulation, but the most common method is to measure body temperature. Here's how to measure body temperature:

2. Use a thermometer. There are several types of thermometers, including oral thermometers, anal thermometers, and electronic thermometers. Make sure you use the correct thermometer.

3. When measuring body temperature, place the thermometer under the tongue and let the thermometer stay in the mouth for 2-3 minutes.

4. Record body temperature. When recording body temperature, record the temperature reading on a temperature sheet and take the measurement at the same time each day.

5. Observe changes in body temperature. After measuring the body temperature, observe the changes in body temperature. Normally, the days when the body temperature rises are the days of ovulation.

By measuring body temperature, we can calculate ovulation. During ovulation, body temperature usually rises for about a day.