Do you know how many days of your monthly cycle you are fertile? Today’s media and your high school health class might have you under the impression that it is possible to become pregnant any time after having unprotected sex. While it is possible, many women are finding it difficult to get

Each month a woman can potentially conceive within a certain time frame called the “fertile window”. Without knowing when your fertile window is each month, conceiving can seem, almost impossible.

No two fertile windows are the same, meaning that it is not always 14 days after your period starts for every woman. This is a very common misconception that is preventing women from moving forward in their family planning goals.

Usually, the fertile window begins 5 days before a woman ovulates and depending on the patterns of your own cycle, it typically lasts 6 days. Each day leading up through ovulation, a woman’s chances of conceiving increase. Because of this, it is likely that the 3 days just before ovulation, your fertility is optimized. Narrowing down your fertile window and therefore your ovulation date can make all the difference in reaching your pregnancy goal.

How to Track

Natural family planning methods monitor a woman’s natural body functions within your monthly cycle. This can aid in pinpointing your fertile window in which you are most likely to conceive.

One of these natural family planning methods is the calendar method, sometimes referred to as the rhythm method. For this, a woman is required to keep a record of her past menstrual cycles, highlighting any patterns of her cycle to narrow down when she ovulates and has her menstrual period.

There are two calculating versions of the calendar method used to get the fullest picture and understanding of all of the possible fertile days- a shorthand version and a longhand version. This two versions can be broken down and used separately from one another, however you may find it more beneficial to use them together.

The shorthand version consists of the following:

  • Estimate approximately when the start date of your next period will be.
  • From that date count back twelve days and then count back four more days. This five-day range will be an approximation of your fertile window for the upcoming month.

This version can help narrow down a fertile time frame for the upcoming month but does not account for any long-term patterns or fluctuations of your cycle and should be used alongside the longhand version for a wider range of possible fertility dates for months to come.

The longhand version consists of the following:

  • Count the amount of days your cycle consists of starting at day 1 which is the first day of your period. Do this for eight to twelve months.
  • Pick out the longest and the shortest cycles tracked during that time.
  • To determine the time frame of your fertile window, you’ll be required to do basic math. Below is the formula of how to calculate your fertile window.
  • In order to pin point your first possible fertile day, take your shortest cycle length and subtract 18 days. Say your shortest cycle was 27 days, subtract 18 and you are left with 9. This means that the 9th day of your cycle is the very beginning of your fertile window according to this method.
  • To find out the end of your fertile window, subtract 11 from the number of days your longest cycle lasted. So if that cycle lasted 30 days subtract 11 and it comes out to the 19th day of your cycle.
  • By following out this equation, you are left with the first and last possible days of a woman’s fertile window. The days in between are the ones a woman is most likely to conceive. The example from shows a fertile window that is most likely to fall somewhere between the 8th and the 21st day of a woman’s cycle.

Although this type of natural fertility awareness method is valid to many experts, using this method alone might not be the most reliable for every woman since not every woman has a regular cycle. However, the calendar method can help you to start listening to your natural cycle and gets you more in tune with your body. Using this method in combination with others can help you optimize your chances of effectively tracking your cycle and to pin point when you ovulate.