Calculate your menstrual cycle

Calendrier papier et application mobile pour calculer son cycle menstruel

From puberty to menopause , a woman experiences approximately 500 menstrual cycles . Of more or less regular duration, they are repeated tirelessly for approximately 40 years, sometimes interrupted by pregnancy or altered by a gynecological disorder . Some experience it spontaneously and intuitively, without any particular follow-up . Others feel the need to know the precise progress, throughout their life as a menstruator or at specific moments of their existence. But why can it be interesting to calculate your menstrual cycle ? And above all, how to do it? Take out the calculator, we'll explain everything to you!

Calculating your menstrual cycle: what’s the point?

Reminder: what is the menstrual cycle?

The menstrual cycle refers to the period between the first day of menstruation and the first day of the next period in women of childbearing age.

In theory, a menstrual cycle lasts 28 days. During this time interval, a series of phenomena occur which allow the female body to prepare for a possible pregnancy. This periodic chain of physiological reactions takes place in the brain, the ovaries, the uterus and the breasts.
From the point of view of the ovaries, the so-called ovarian cycle is commonly broken down into 3 phases.
  • The follicular phase, also called preovulatory phase since it takes place from the 1st day of menstrual bleeding until ovulation, lasts on average 14 days (this is the phase of the cycle whose duration varies the most from woman to woman). to the other).
  • The ovulatory phase, or more simply ovulation, which corresponds to the release of an egg from an ovary, theoretically occurs on the 14th day.
  • The luteal phase is the postovulatory period: it begins after ovulation and continues for 14 days (fixed duration in the majority of women), until the onset of the next period.

During each menstrual cycle, a pregnancy can occur during a period of approximately 6 days: this is called the fertile window. The latter generally begins 5 days before ovulation and ends 1 day after ovulation.

Why calculate your menstrual cycle?

Know how your body works

The figures previously given are theoretical. In reality, there is great variability within the female population. Only 10 to 15% of women have a cycle that is exactly 28 days long. In general, the length of menstrual cycles ranges from 21 to 38 days.
Calculating your menstrual cycle according to your personal situation (age, state of health, method of contraception, etc.) allows you to estimate its own average duration. This makes it easier to know when your next period is coming, which allows you to prepare for it and avoid accidents.
In addition, it is interesting to take note of your physical and psychological feelings from day to day over the long term. This can help you better manage your daily life, by capitalizing on moments of dynamism and slowing down when fatigue is more present. The diagnosis of PMS is also made easier.

Calendar to calculate the date of your period

Being able to influence certain gynecological events

Monitoring your menstrual cycle to know its usual course also allows:

  • to increase the chances of getting pregnant, by identifying periods of ovulation and therefore fertile windows to plan sexual relations during them;
  • to prevent an unwanted pregnancy by choosing suitable contraception;
  • to identify abnormal events ( heavy periods , pain , mood changes , etc.), signs of a possible medical problem (menstrual disorder, endometriosis , polycystic ovary syndrome, etc.);
  • to detect the arrival of menopause and to manage its manifestations as best as possible.

How to calculate your menstrual cycle?

Keep a calendar to track your menstrual cycle

Over several consecutive cycles:
  • note the date of the start of each period;
  • note the date of the end of each period;
  • Write down your possible physical and emotional feelings every day.

Write down the dates in a calendar to calculate your menstrual cycle

After several months:

  • deduce the average duration of your menstruation (equal to the sum of the number of days between the start and end dates of your period over all the cycles considered, divided by the number of cycles considered);
  • deduce the average length of your menstrual cycles (equal to the sum of the number of days between each period start date over all the cycles considered, divided by the number of cycles considered);
  • deduce your ovulation date, by subtracting 14 days (which correspond to the luteal phase) from the average length of your menstrual cycles (for example, if your cycles last on average 26 days, your ovulation takes place on the 12th day [26 – 14 = 12]);
  • identify the phenomena that repeat each cycle.

Calculator to track your menstrual cycle

Track your menstrual cycle: paper or digital?

It is entirely possible to follow your cycle with just a paper calendar and a pencil. But it still turns out to be tedious! And the calculations are relevant if you have a fairly regular cycle. This turns out to be much more complicated and much less usable if your cycle is irregular. Why not use one of the many mobile menstrual cycle tracking applications? You enter the dates of your period and note all your observations; they automatically calculate the data that may interest you – date of the next menstruation, duration of periods, length of the cycle, fertile period – while analyzing the variability of the phenomena.

Mobile application to calculate your menstrual cycle


And you, do you calculate your menstrual cycle? To do this, do you use a mobile application? Do you find this useful and effective? In any case, if you have questions or concerns about your menstrual cycle, contact a health professional: only he or she will be able to provide you with reliable answers and personalized solutions.

To extend reading:

Written by cd

Blog