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It’s common to dread your menstrual cycle. After all, period symptoms can take a toll on your body, mind, and daily life. It is important to note that severe pain with your periods is never normal and should warrant a visit with a Gynecologic specialist.

But knowing when your period may start and how long it may last can help you take better control over your physical and mental health.

This primer explains how menstrual cycle tracking, or period tracking, works and introduces some tools that can make it easier.

Menstrual Cycle and Period Tracking

Your menstrual cycle is the monthly hormone changes your body goes through to get ready for pregnancy. Menstrual tracking means recording these days to find the length of your menstrual cycle.

To count the days in your cycle, you count from when you start period bleeding one month to the time you start period bleeding the next month.

What’s a normal menstrual cycle?

A normal, or regular, menstrual cycle lasts anywhere from 24 to 38 days. Even if your period isn’t the same length from month to month, you still have a regular cycle if it falls within this range. The average menstrual cycle lasts about 28 days, although most women have cycles that vary by a few days.

Regular period bleeding lasts eight days or less. Bleeding that lasts longer than eight days is called prolonged menses.

What are irregular cycles?

Irregular cycles are those that come more often than 24 days or last longer than 38 days. If you have irregular cycles or prolonged menses, tell your doctor. They may point to one of many underlying health issues, such as polycystic ovary syndrome (PCOS).

Benefits of Period Tracking

Everyone’s menstrual cycle is different, and period tracking can help you figure out your menstrual cycle. Plus, as you age, your menstrual cycle changes.

If you have regular periods, tracking your menstrual cycle and related symptoms can help you identify:

• Fertility window (when you’re most likely to get pregnant).
• Ovulation (when your ovaries release an egg).
• Period symptoms, such as heavy or painful bleeding, and how long they may last.
• Start date of your next period and how long it may last.
• When you’ve entered perimenopause (the transition from your “fertile years” to menopause, when periods stop for good).

If you have an irregular menstrual cycle, menstrual tracking isn’t as helpful for period planning or fertility planning.

Period-related health issues

Period tracking information can help you and your doctor manage menstruation-related health issues. This includes:

• Adenomyosis.
• Endometriosis.
• PCOS.
• Premenstrual dysphoric disorder (PMDD), a severe form of premenstrual syndrome.

Knowing what to expect can help you prepare for painful or bothersome symptoms ahead of time.

Mental health benefits

Period tracking may also help if you have certain mental health issues. A 2023 report in the Journal of Psychological Nursing and Mental Health Services links changes in sex hormones during periods to several worsened mental health problems and increased suicide risk. This includes bipolar episodes, depression, eating disorders, PMDD, post-traumatic stress disorder, and sleep problems.

The main mental health concern comes during a menstrual cycle’s mid-to-late luteal stage — the time between ovulation and when the next period starts. During this stage, estrogen and progesterone levels are high and may yo-yo.

How Do I Track My Menstrual Cycle?

There are two ways to track your menstrual cycle.

Calendar method

You can track your period cycle using a simple paper calendar or an online calendar on your smartphone or computer. Follow these steps:

• Start by marking the day you start your period on the calendar. A simple X will do.
• Mark an X on each day until bleeding ends.
• Repeat the next month.
• After a few months, see if your periods are regular or if the cycles vary.
• Add your cycle length to the first day of your last period to get the start date of your next period. For example, if your period starts on March 1 and you have a 30-day cycle, then the first day of your next period may begin on March 31.
• Continue marking your period start and end dates each cycle.

Period symptoms to track that doctors may find helpful include:

• Belly pain and cramping.
• Bloating.
• Breast swelling or tenderness.
• Forgetfulness.
• Headaches.
• Heavy bleeding (track the number of pads or tampons you use, and the days you have heavy bleeding).
• Moodiness.
• Missed work or school because of period symptoms.
• Spotting between periods.

Period tracking apps

You can also use menstrual cycle tracking apps on your smartphone or computer. Before using these, be sure to review the privacy or data sharing agreements in place with the apps, as they may be shared with a third party. These digital tools use data you input and an algorithm to predict your next period, ovulation, and fertility window. Most start with a 28-day cycle and adjust as you input more period start dates.

Many apps also let you track pain, period symptoms, energy, and activity levels. Some can graph or chart pain across period cycles.

Some apps also offer health tips along with mindfulness and meditation features to help you manage period symptoms.

Other at-home fertility tracking

Because cycle lengths can vary, period tracking alone can’t always pinpoint your fertility window or ovulation. Period tracking apps predict the day of ovulation with only 21% accuracy, a 2018 study in Current Medical Research and Opinion found.

The most accurate at-home fertility tracking and ovulation predictor? Ovulation test kits that measure luteinizing hormone in your urine, which spike the day before ovulation.

What about wearable devices?

Several wearable devices for menstrual and fertility tracking — like watches and rings — have hit the market in the last few years. Most use body temperature to determine when you’ll start your period and ovulate. According to a 2024 systematic review in the Journal of Medical Internet Research, more research is needed to know whether and how well these work.

Choosing and Using Period Trackers

Most period tracking apps are free to download. You may need to try a few to find one that works best for you.

Keep in mind that these apps rely on the data you input. Make sure you enter the correct date your period starts, or you won’t receive accurate predictions for your next period.

Whatever app you use, read and understand your privacy protections and data usage. Period tracking apps collect personal and sensitive health information. A 2025 study of 14 menstrual health apps published in BMC Women’s Health found over 71% shared user data with third parties.

The Health Insurance Portability and Accountability Act of 1996 (HIPAA) protects the privacy of health information held by a medical provider, such as a doctor’s office or hospital. HIPAA generally doesn’t protect health information you enter into non-covered period tracking or other consumer-based health apps.