With a 25-day menstrual cycle, the day of ovulation is the 11th day of the menstrual cycle, which is the 14th day before the next period. If you want to calculate ovulation more accurately, you can also measure your basal body temperature. Find a temperature chart, wake up every morning, take your temperature before you get up, record it after taking your temperature, and after 1 month, connect the measured temperatures into a line, you will find that your temperature has increased by 0.3-0.5 degrees Celsius. Another method is to use LH test strips, which is simple and convenient, and can be done by measuring morning urine. If estradiol rises to about 200pg and LH also rises significantly, then ovulation should occur.