Menstrual Cycle Calculator: What is it and How Do I Use it?

A menstrual cycle calculator can be a very useful instrument when it comes to understanding your body and planning your life accordingly. For example, when you know what to expect from a normal cycle, you can better recognize abnormalities or plan out pregnancies. Additionally, a menstrual cycle calculator is useful in planning simple things, such as when to go on vacation.

Understanding your menstrual cycle

Before understanding how to calculate your menstrual cycle, its useful to understand the various phases that your cycle goes through. Menstrual cycles generally have three phases. First is the follicular phase, followed by the ovulation phase and then the luteal phase.

The follicular phase begins on the first day of menstruation, which is when the egg is formed. The follicular phase will continue until the beginning of the ovulation phase. Somewhere between the 12th and 16th day of the menstruation cycle, the ovulation phase begins. The exact day of ovulation depends on the length of your cycle. Most cycles are 28 days, but some cycles are longer or shorter.

After conclusion of the ovulation phase, the luteal phase begins. The luteal phase is when the period occurs and the egg is released. When planning for pregnancy, it’s important to remember that high fertility usually begins 5 days prior to ovulation and ends approximately 2 days after. Using a menstrual cycle calculator will enable you to determine when this timeframe actually begins.

Calculating your menstrual cycle manually

There are many ways to calculate your menstrual cycle—some more involved than others. The easiest way is simply to count days on a calendar. By recording on a calendar the first day of your last period you can determine where your menstrual cycle begins. Your menstrual cycle begins on the first day of your last period and runs through the last day before your next period. Once you have determined the beginning and end of your menstrual cycle, you can calculate when your body is going through each of the phases above.

Another menstrual cycle calculator is a bit more involved, but allows you to more closely monitor your cycle. This method uses your body temperature to determine your ovulation day. You will need a few things before you begin, including graph paper, pencil or pen, and a basal body temperature thermometer.

The first step is to create a chart. You begin by labeling the vertical axis “Temperature” and bottom horizontal axis “Day.” The vertical axis will be used to record your temperature readings, so write numbers 97.0 through 99.5 along the axis. Make sure each interval along the vertical axis is a tenth of a degree. Then, along the bottom horizontal axis, number each square 1 through 28, to indicate the number of days in your cycle. If you so choose, you can also use the top horizontal axis to indicate the specific day of the year, for example “September 1, 2010.”

Once your chart is constructed, begin recording your cycle on the first day of your period. On cycle day 1 (the first day of your period) write the letter “P” underneath the number 1 on the bottom horizontal axis. Write this letter “P” underneath each day that you have your period.

On cycle day 2, or the second day of you period, begin taking and recording your temperature. The best time to take your temperature is first thing in the morning. Try to take your temperature at the same time every morning and make sure you have gotten a good nights rest. Using the basal body temperature thermometer, take your temperature and record it on your chart. Simply write a small dot next to the number on the vertical axis that matches your body temperature and above the number on the horizontal axis that matches the day. Take your temperature every day and connect the dots on your chart.

By reading the results on your chart, you should be able to determine your ovulation day. You should notice a .4 degree F rise in your temperature that lasts for at least 3 consecutive days. Ovulation typically occurs on the day before you actually have the rise in temperature. Indicate on your chart the day you ovulated by making a noticeable mark underneath that day. You can now determine when you are most fertile by remembering that the period of high hertility is generally from 5 days before the ovulation day through 2 or 3 days after your ovulation day.

Electronic menstrual cycle calculators

In addition to manually tracking your menstrual cycle, there are devices that can calculate your cycle for you. Frequently, these menstrual cycle calculators are also referred to as pregnancy calculators, ovulation calculators and other similar names. However, electronic menstrual cycle calculators still provide you with much of the same information that the chart will provide you with, including your ovulation day, days when you are most fertile and when your next period will occur. Also, most of these devices are fairly accurate.

Most electronic menstrual cycle calculators detect the luteinizing hormone in your body, which assists in tracking your cycle. Specifically, with an electronic device, you should be able to determine the 2 days you are most fertile, as well as 5 other days of high fertility. Typically, electronic menstrual cycle calculators present the data concerning your cycle in a graph that is easy to read.

Deciding whether to purchase an electronic menstrual cycle calculator, or to do it manually, is really dependent on whatever works best for you. If you do not think that you will remember to record your temperature every morning, then maybe an electronic calculator is more appropriate. However, of you like the idea of being more involved in the process, then a manual cycle calculator might be the option for you. Either way, a menstrual cycle calculator is a useful tool in understanding how your body works and in making family and life plans.