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Period Calculator

Plan ahead. Predict when your next period will arrive. Get insights on your cycle.

period-image

Create your period schedule

List the first day of your menstrual period, also known as the start to your menstrual cycle.
This refers to the duration of time spend bleeding or the number of days that you experienced vaginal bleeding during your cycle. It can be measured from the first day you notice bleeding through the day bleeding stops.
(days)
A full menstrual cycle refers to the length of time from the beginning of one period to the first day of the next period. For example: If your last period started on January 1st and your next period started on February 2nd, your menstrual cycle length would be 33 days.
(days)
 
This tool is not intended to be medical advice and should not be used to prevent pregnancy. Results are an estimate and may vary for each woman. Your privacy is important to us and we want to ensure you have control over your data. The information you provide will be used to personalize your experience with U by Kotex® and Kimberly-Clark® brands so that we can make our offers more relevant and send helpful reminders if interested. This includes using your information to better market and advertise our products to you. If at any point you no longer want these benefits, you can unsubscribe directly below. You can also submit a request to delete your information below.
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Track Your Cycle Today!
Your period is a natural and normal part of your life, which is why understanding when your cycle starts shouldn’t be a mystery! With our fun and easy-to-use period tracker, you’ll get instant data to help you be prepared and better understand when your next menstrual cycle starts and ends! Let’s learn more and get tracking!
FAQs

A period calculator is an informative online tool used to determine the start of your menstrual cycle. This is based on data you provide from your last cycle to predict the date of the first day of your next cycle. Period calculators are personalized and designed for you - so you never have to guess when your cycle starts. 

A period tracker works by determining the start of your next cycle by placing in the dates from your last cycle. Then, you input the number of days you bled (generally 5-7) and what the typical length of your cycle is. On average, menstrual cycles last for 28 days, which means there are 28 days from the first day of one period to the first day of the next. However, your period might be shorter or longer (21-35 days), depending on how long you’ve been menstruating, your age, activity level, and other lifestyle factors! Tip: If you know the start date of your last two periods, you can count the number of days from day one of the earlier period to day one of your most recent period. This will give you the length of your menstrual cycle!4

To recap, you’ll need:

  • The first day of your last period
  • How many days your period lasted in your last cycle
  • The length of your menstrual cycle

The period tracker can also help you calculate your ovulation date! Your date of ovulation is when the egg is released from your ovary. You may have noticed on the calendar that in addition to menstruation being outlined in red, there are also dates outlined in blue. In our example above, those dates are August 17-21 and September 14-18. These dates are your peak ovulation days. In a 28 day cycle, the expected date of ovulation is day 14, i.e. two weeks before your next cycle begins. If your cycle is shorter or longer (or if you haven’t been counting every day since your period ended) that date could change and that’s where the period calculator comes in. These dates outlined in blue are your most fertile days, in the event that you’re trying to become pregnant. Once released, the egg can live up to 24 hours while sperm can live for up to 5 days.

Like we said above, the average length is about 5 days but remember, there’s always variation! Anything from 2-7 is considered normal. It’s possible that you’ll see light brown discharge for the final few days, so you can try a Light Days Plus liner for your lighter flow.

While tracking is a great way to determine when to expect your menstrual cycle to start, here are some other signs that might indicate your period is coming.

To recap, you’ll need:

  • Bloating
  • Cramps
  • Breast tenderness
  • Mood swings/irritability
  • Insomnia
  • Acne
  • Joint pain
  • Increased anxiety
  • Back pain
  • Fatigue
  • Feelings of

Note: These symptoms are a general overview and may not indicate your period is coming. If these problems persist, reach out to your doctor.

Menstrual tracking or cycle tracking is an important way for you to understand when your period starts. It is also an easy way to empower yourself to understand your health and your body. As women, our bodies can fluctuate and change over the years. Understanding your menstruation cycle can help you to better understand your reproductive cycle as well as to help you identify any changes in your body. If you’re bleeding heavier than normally or miss a period, cycle tracking can help you see the data to potentially share with a doctor. Knowing your cycle can also help you plan social outings, events, and vacations.

Curious about how long you’ll be using a period calculator? The transition to post menstrual life begins between 45 and 55 years old, with 51 being the North American average for menopause.

Period irregularity is par for the course, especially when you first start getting your period. In the beginning, you will likely experience irregular cycles and some spotting. It might take time for your body to find its rhythm, but you should notice a more regular cycle as you get older. Changing hormones can also shift your cycle, which typically happens around puberty, pregnancy, and menopause. Other factors such as stress, excessive exercise, medical conditions such as PCOS or thyroid conditions, age, diet, giving birth and breastfeeding could also cause changes. If you feel something is off, always reach out to your doctor for support and help!