When is My Period Due? How to Calculate and Keep Track of Your Cycle
Updated: Mar 26, 2019
Are you one of those people who keep feminine products in your purse “just in case” you need them, because you have no idea when your period is due? Do you have an idea about when it possibly should arrive, but you aren’t really sure? Read on to learn how to calculate your cycle, so you don’t have to ask yourself, when is my period due? anymore!
The average woman’s cycle is about 28 days long…but we all know, women are anything but average. Our bodies are unpredictable, hormone-controlled, unregulated powerhouses that are capable of super powers like growing humans.
The only problem is, in order to grow those humans one day, we have to go through the annoyance of having a period each month, maybe. We never know what’s going to happen.
If we’re lucky, we have a regular, or fairly regular, cycle. A lot of women never know when their period will come. Between stress, hormones, life, health, etc., there are numerous things that can make you miss a period, make it late, or change it.
SO, When is My Period Due?
If you google that phrase, you will be bombarded with 100s of period calculators, menstrual calendars, ovulation predictors, etc. They all work off of the basic math that I’m going to teach you today. (Later I will give you a link to my favorite tracking app).
First of all, as I mentioned before, the average cycle is 28 days. You’ll need a calendar to track the days between your cycles. Let’s just use 28 days for now.
Day 1: Your Period
Next, you’ll count the days starting from the first day of your period. That’s day 1. You count out how many days your period lasts. The average is 5 days. Women are considered fertile between days 8 and 21. This is shortly before, during, and after ovulation is most likely occurring.
Days 12-18: Ovulation
Once you determine how long your cycle actually is, you can subtract 12 (or 14, according to THIS article) days from your next period start day, and that’s the day you should be ovulating. If your cycle lasts 30 days, subtract 12 and that means you should ovulate on day 18. If your cycle is 26 days, subtract 12 and you should ovulate on day 14, and so on.
If you’re trying to get pregnant (or trying to prevent pregnancy, although this is not a reliable method!), you’ll want to know that sperm live inside the woman’s body for 3-5 days.
Days 21-28: The "Infertile Period"
The cycle’s “infertile period” is the time between the “fertile period” and the day your period starts. This occurs around days 21-28 (or longer if you have a longer cycle).
This time frame is considered infertile because it is “too late” for the egg to become fertilized. It has already begun to degrade. Remember, sperm can live for 3-5 days, so also use that as a cushion if you’re trying to PREVENT pregnancy.
Again, don’t rely on this as a form of birth control because it is NOT an exact science. Many extenuating circumstances could delay ovulation and you could still end up pregnant during the so-called- “infertile” time.
If your period is regular, you have a much higher chance of succeeding with Natural Family Planning (fertility awareness) methods.
Your period will occur right after this “infertile” time frame. Usually it will come after days 28-32. You then start over at day 1 and the whole thing begins again.
How Do I Keep Track of This Stuff?
There are many ways to track your cycle. One way is just to use a good, old fashioned calendar. However, modern technology has made it much easier. There are several apps for your phone that help you stop asking, “when is my period due?”
THIS article lists some of the best-rated period tracking apps for both iPhone and Android. The first one on their list, Period Tracker, is my favorite.
Period tracker makes it super easy to track your period and ovulation. If you purchase the app instead of using the free version, it has different modes (such as pregnancy mode) that you can use.
It also has different themes, so you can find something to fit your style. It has cute little icons for things, and in the paid version you can share data with your partner.
This app tells you when your next period (should be) due. Once it gets to know you a little (after a few months), it will be really accurate. It puts an icon on your ovulation day and little green dots on your fertile days. Here is a link to the free version of the app. It’s only available on iPhone.
If you need a little help getting your period to be more predictable, try Bioterra Herbs’ Female Fertility supplement. It’s not just for getting pregnant! It can help regulate your period so you can keep track and have a family when you’re ready!