Content

• To step
• Method 1 of 4: The Calendar Method
• Method 2 of 4: The Cervical Mucus Method
• Method 3 of 4: The Temperature Method
• Method 4 of 4: Other Methods
• Tips

Ovulation occurs when a fully grown egg comes out of the ovary and travels down the fallopian tube in hopes of being fertilized by a sperm cell. Since ovulation is the time when you can get pregnant, it can be very helpful to know how to calculate when this will occur. However, every body is different and so there is no mathematical formula that just applies to everyone. However, there are ways to calculate when you will be at your most fertile. If you want to make sure that your calculation is correct, it is best to apply all the methods below.

To step

Method 1 of 4: The Calendar Method

1. Buy a calendar and start tracking your cycle. Circle the first day of your cycle, which is the day you have your period. Keep track of how many days your period lasts.
   • Count the number of days each cycle lasts, including the day of your period. The last day of each cycle is the day before your next period.
   • Write down the course of about eight to twelve cycles in this way. The more you keep track of, the more reliable the calendar method will be.
2. Plot the eight to twelve cycles you recorded. In one column, write the day of your period and in the second column the number of days your cycle lasted.
3. Use your graph to predict the fertile period in your current cycle. It is difficult to know exactly what day you will ovulate. Thanks to the calendar, however, you know approximately on which days you will be fertile.
   • Predict the first fertile day in your current cycle by looking up the shortest cycle on your chart. Subtract 18 days from the total number of days that cycle lasted. Add the number left over to the first day of your current cycle and mark the date you come out. This is the first fertile day in your cycle - that is, the first day you could get pregnant.
   • Predict the last fertile day by looking up the longest cycle on your chart. Subtract eleven days from the total number of days the cycle lasted. Add the number left over to the first day of your current cycle and mark your release date. This is the last fertile day in your cycle - the last day you can get pregnant.
   • The number of fertile days can differ per woman.

Method 2 of 4: The Cervical Mucus Method

1. Cervical mucus has a specific function in the female body. It is there to protect the cervix. You can tell when you ovulate from the amount of mucus your body produces. To stimulate fertilization of the egg, the body produces slightly more mucus than normal around ovulation. Once you are aware of this, you can use it to predict the day you will ovulate.
   
   
2. Make a chart based on your amount of cervical mucus. Write down changes you are going through (how best to do this can be found in How to Check Cervical Mucus.) Record the changes in a diary or on a calendar.
   • Write down when you have your period, when you are producing little mucus, and when the mucus is slightly thicker or wetter.
   • Write down when the slime has a different color, texture, or odor.
   • Keep your diary or calendar as good as possible, especially in the first few months when you still have to get used to the method.
   • Breastfeeding, infections, certain medications, and other conditions can affect your cervical mucus. Therefore, make sure you also write these things down.
3. Read on the day you ovulate based on your cervical mucus. The day you ovulate is usually the day when your cervical mucus feels very wet and slippery. You will be least fertile in the days after this peak.

Method 3 of 4: The Temperature Method

1. Buy a basal thermometer. Your body temperature is lowest during the first part of your cycle and rises slightly when you ovulate. Then your temperature remains constant for the rest of your cycle. Measure your basal body temperature at a quiet time. Keep your temperature in a diary for about three months. Based on the collected data, you can predict approximately when your ovulation will occur. Because the temperature difference between your fertile and non-fertile period is so small, it is better not to use a normal thermometer. Basic thermometers are available at pharmacies and drug stores.
2. Make a graph on which you can read the development of your body temperature. Keep track of your temperature on a graph in which you can keep track of changes. Take a look at Baby Center Sample Chart for example.
   • For the most reliable possible result, it is important that you take your temperature around the same time every day. This is best done in the morning, as your body is then fully rested.
   • The most accurate measurements are those in the vagina or rectum. If you prefer, you can also purchase a thermometer that can measure your temperature in your mouth.
   • A woman's average body temperature is between 36.5 and 37.5 degrees before ovulation. After ovulation there is an increase in temperature of about 1 degree.
   • When keeping your temperature, also write down the number after the decimal point.
3. Read the course of your body temperature. Once you've been tracking your temperature for a few months, you should see the dates when your temperature rises - the day you ovulate. Based on this data you will be able to predict approximately when you will be fertile.
   
   

Method 4 of 4: Other Methods

1. Use an ovulation test. Ovulation tests are available in pharmacies and drug stores. The test measures the presence of the luteinizing hormone (LH hormone) in your urine. This hormone increases about two days before ovulation.
   • Ovulation tests accurately indicate the presence of the LH hormone in your urine. However, keep in mind that there is always a little bit of the hormone in the urine. The fact that the hormone is measured does not necessarily mean that you are ovulating.
2. Use an online ovulation calculator. All kinds of websites are available for this.
   • Online ovulation calculators are standardized and so will not be as accurate as other measurement methods.

Tips

• Stress, eating habits, exercise, and a number of other factors can affect your cycle on a monthly basis. Take about a year to measure your cycle in different ways. The more methods you use, the more insight you will gain into your cycle.
• The idea that most women's cycle lasts 28 days and you can predict ovulation by adding 14 days to the first day of the cycle is outdated. For some women the cycle lasts only 21 days, for other women 36 days and there are countless other variants. A woman's cycle is personal and applying the above methods is the only way to actually gain insight into this.
• If you want to calculate your ovulation to avoid pregnancy, remember that it is very difficult to calculate the exact fertile days. The above methods are just ways to calculate when you are most fertile.