If you want to plan a family, then you may want to use a calendar to keep track of your menstrual history. Men may feel awkward discussing this. But, it’s a natural part of life that can help you and your partner predict when ovulation will occur. Knowing this information can help determine when the best time to conceive will be. Women will want to consider making and keeping an ovulation calendar.

Don’t even think about using these methods if you are preventing pregnancy — (think double-bright-red-exclamation-point-emoji’s here).

Additionally, this method, which is referred to as the rhythm method, can also be used to prevent pregnancy. While this isn’t a recommended form of contraception, couples have used it as a way to identify the days to avoid unprotected sex. It may also be used to help women figure out when it’s healthy to conceive. For example, in-between childbirths or when you stopped taking birth control pills.

Of course, you should still speak with your health provider before using an ovulation calendar in any of the examples listed above. While it can assist with timing if trying to get pregnant, an accurate calendar or calculator does not exist. But, it still may be useful in helping you narrow down when you’re fertile.

If you believe that an ovulation calendar can be helpful, enjoy this introductory guide. It will provide a brief history of fertility charting, how an ovulation calendar works, and how to to create one of your own. It will then conclude with some more accurate methods of ovulation detection.

History of Fertility Charting

As explained over at FertilityFriend.com, “Prior to the 20th century, a great deal of superstition and misinformation surrounded fertility and the menstrual cycle.” It’s only been within “the last century and a half” that “multiple observations from a variety of researchers contributed to our current understanding of the meaning of our fertility signs.”

It is somewhat strange that we still don’t talk about this information much — and it doesn’t mean that society has more recently been aware of what part of the menstrual cycle is the most fertile. St. Augustine is said to have discussed this back in 388 by saying, “Is it not you who used to counsel us to observe as much as possible the time when a woman, after her purification, is most likely to conceive, and to abstain from cohabitation at that time…?”

The Greek physician Soranus also made inaccurate statements like “the time directly before and after menstruation” was the most fertile part of a woman’s cycle.” The same type of information has been repeated by the Byzantine physician Aëtius in the 6th Century. There’s also a manual from China dating from 600 that women were most fertile during the first five days following menstruation.

It wasn’t until 1855, however when advancements in this area took great strides. “W. Tyler Smith observed that cervical fluid offers a medium well-suited for the passage of sperm, and in 1868, J. Marim Sims described cervical fluid as having the consistency of a white of an egg.”

In 1868, Squire, and then Mary Putnam Jacobi in 1876 made the “first observations that the basal body temperature has a biphasic (low temperatures followed by high temperatures) pattern during the menstrual cycle.”

The O.K. Method

“In 1905, Theodoor, Hendrik Van de Velde, a Dutch gynecologist, published a series of biphasic charts and noted that the length of elevated temperatures before menstruation was independent of the length of the menstrual cycle, thus demonstrating that the luteal phase is constant,” notes FertilityFriend.com.

“In the 1920s and 1930s, two gynecologists, Kyusaku Ogino in Japan and Hermann Knaus in Austria, studied ovulation carefully,” explains Case Western Reserve University. “They concluded that it normally occurs from 12 to 16 days before the onset of the menstrual period.” Ogino and Knaus “also asserted that an unfertilized ovum had a brief life, probably less than a day. At last, it seemed, the ‘safe period’ could be more accurately determined.”

However, while at the same time but separately, Ogino and Knaus used this information to “develop the largely ineffective calendar rhythm method of birth control.” This method was also championed by individuals like Leo Latz, a doctor from Chicago who also published “The Rhythm of Sterility and Fertility in Women” in 1932.

The calendar rhythm method was replaced in 1935 by a German Catholic priest named Wilhelm Hillebrand. But, in the proceeding three decades, researchers continued to make advancements. Most notably by Professor John Marshall and the World Health Organization in the sixties who developed the “covering method” and “three over six” method where “a trained couple simply had to observe three temperatures higher than the previous six to identify when ovulation occurred.”

From the Rhythm Method to Natural Family Planning

However, in 1970, the rhythm method began to fall out of favor — gratefully. Most people using the rhythm method became commonly known as “parents.” The technique fell out of favor in part to V. Insler, who “published a method of ‘scoring’ cervical fluid according to its characteristics.” John and Evelyn Billings also used similar observations and came up with their own system, known as the ‘Billings” or “Ovulation’ method. The “Billings” method, much like the rhythm, taught “women how to observe and chart their cervical mucus signs to recognize their own fertility pattern.”

In other words, ovulation calculating was no longer used for contraceptive purposes. It was more focused on assisting with natural family planning.

By the eighties and nineties, technology allowed medical professionals and researchers began to use “high-tech methods of ovulation detection at this time.” People could also turn to the internet to locate information on ovulation calculations. And, today, numerous apps have brought fertility charting to the palm of your hand.

What’s an Ovulation Calendar, and How Does it Work?

Now that we’ve gone over the history of fertility charting, albeit briefly, let’s go over what an ovulation calendar means today.

In its purest form, an ovulation calendar or calculator is simply a tool that can help predict when you’re going to ovulate. Knowing this allows you to identify when the best time to have intercourse will if you’re hoping to conceive.

Charting is based on menstrual cycles. However, other information like ovulation symptoms, sex attempts, and basal body temperature can also be used to let you know when you’re most fertile. You can keep track and chart this data either by using a paper or online calendar. But, there are also numerous computer programs and apps that may be more accurate.

Again — only use ANY of these “ways” of keeping track of your body’s functions — if you want to get pregnant!

How an ovulation calculator works.

“The most basic ovulation calculator will ask you for the date of the first day of your last period, and the average length of your menstrual cycles,” writes Rachel Gurevich for Verywell Family. “If you don’t know, most calendars will suggest you write in 28 days.” The reason for this is that 28 days are considered the average cycle. But, regular ovulation cycles can range from 21 to 35 days.

From there, “the calculator will usually assume a luteal phase of 14 days,” adds Gurevich. “The luteal phase is the time between ovulation and the first day of your period.” Typically, this phase is between 10 to 15 days. Not all ovulation calendars will ask how long your luteal phase is, but the nicer ones will. You can locate this, and then input into your chart, by reviewing your previous basal body temperature to determine how long yours is.

“Next, based on this information, the ovulation calculator will guess what days you are most likely to be fertile, and perhaps the day you may ovulate,” explains Gurevich. So, for example, if “you told the ovulation calendar that your average cycle is 35 days, and your average luteal phase is 15 days, it may display your possibly fertile days as day 17, 18, 19, and 20 of your menstrual cycle.” How did it come up with this figure? It counts 15 days backward from the 35th day of your cycle.

In should be noted that “some calendars will indicate ‘possible fertile’ days and ‘most fertile days,’ with the most fertile days in our example on days 19 and 20.”

Ovulation for a boy or girl.

While indeed not an exact science of any kind, you can also use an ovulation calendar to figure out the sex of your child by the date of conception. This is called the Shettles Method. It was introduced in the 1960s by Landrum B. Shettles and highlighted in the book How to Choose the Sex of Your Baby. As explained by Nicole Harris in an article on Parents.com, “Y-sperm (which produces males) supposedly travels quicker through the reproductive system and has a shorter life span. Therefore couples wanting a boy should have unprotected sex close to ovulation.”

X-sperm (which produces females) moves slower and has a longer life span. If you have sex a couple of days before ovulation, the X-sperm will still be around when you ovulate, while the Y-sperm will die,” adds Harris. “This may increase your odds of having a girl.”

How to Create Your Own Ovulation Chart

Even if a woman has the same cycle, they may ovulate at different times. In other words, everyone’s cycle is different. The good news is that you can create your own template rather easy. Again, it’s not 100%. But, it can give you an estimate on when you may be the most fertile.

With that said, here’s how what you’ll need to use this chart:

    • The average number of days in your cycle. This would be the days from the start of one period, and the next one begins.
    • How to count cycle days. Cycle Day 1 would be the day that you get your period. Cycle Day 15 then would be 15 days later and so forth.
    • The information you add to the chart is an estimate. For a more accurate figure, include data like basal body temperature charting.
    • You’re most fertile one to two days before ovulation. “Ovulation lasts for 12 to 48 hours, but you are potentially fertile for up to seven days, and maybe up to 10 days, according to the most optimistic studies, writes Gurevich in another article. “This is because sperm can survive up to five days in the female reproductive tract.”

What if your period is irregular?

Christine Porreta writes on Momtastic that you would want to:

  • Keep track of your menstruation on a calendar for at least six months.
  • Subtract 18 days from your shortest cycle.
  • Subtract 11 days from your most extended cycle.

While you can use your existing paper or online calendar, there are a variety of ovulation templates that you can download and print. Vertex42 has an Excel template as an example. But, you can use this classic pregnancy chart template or purchase a workbook like “Honoring Our Cycles: A Natural Family Planning Workbook.”

You can also use websites that contain built-in ovulation calendars. Simply input the required information, such as the first date of your period and the average length of your menstrual cycle, to receive a rough estimation on when you’re most fertile.

Examples include:

Ways to Track for Ovulation

The calendar or rhythm method is not the only way that you can track for ovulation. There are a variety of other ways of doing this. These include:

Basal body temperature readings (BBT).

A woman’s body temperature rises after ovulation. However, that doesn’t mean this is the best time to conceive. It’s actually right before you ovulate. It takes some work to track this cycle. But, it can be useful in identifying your specific fertile patterns.

You’ll first need to purchase a BBT thermometer and take your temp first thing in the morning. Track this cycle for several months. The thermometer can aid you in learning your body’s rhythm. As a result, you’ll be able to predict when ovulation occurs.

Standard days method.

The Standard Days Method is a variation of the calendar method. It’s usually used by women who have cycles between 26 and 32. Additionally, it’s used alongside CycleBeads. These are color-coded fertility beads that help determine your best chances of ovulation — usually on days 8-19.

Symptothermal method.

The syptothermal method is a combination of the calendar, temperature, and cervical music techniques. Medical professionals have described this as a “smart move”. Using this method is only smart if you “hope” to get pregnant. Using a variety of ways is often more useful for getting pregnant — than relying on just one type. But still, most of these are working as a placebo for a hopeful baby event.

What’s more, there are more advanced ovulation tracking methods. These include:

While an ovulation calendar can be useful — but it doesn’t guarantee that you will successfully conceive. It’s meant to provide you with a rough estimate of when the best possible times to conceive may be. As such, you should consult with your health care provider.