Before we dive in, let’s go over the difference between your menstrual cycle and your period.
The menstrual cycle is a sequence of hormonal events (including ovulation) that prepares the body for a potential pregnancy approximately once a month. Periods, on the other hand, mark the beginning of each new cycle. They happen when the inner lining of the uterus (endometrium) sheds, which causes bleeding. Both menstrual cycle length and period length vary from person to person, and it’s normal for them to vary in length for a single person too.
Menstrual cycles vary in length, but any length from 21–35 days is considered normal for adults. For the first two years you get periods, menstrual cycles can last 21–45 days and still be considered normal.
In 2020, Flo collaborated with the University of Adelaide to conduct a large study using anonymized data from our app. After studying the data of over 1.5 million people, we found that over 90 percent of people who get periods had a menstrual cycle that was 21–35 days long. Interestingly, only about 16 percent of the participants had a 28-day cycle, even though you might have been told this was the typical length for menstrual cycles.
A study carried out from 2013–2018 of the menstrual cycles of more than 98,000 women showed that the average duration was around 30 days.
Enough about menstrual cycles — how long does a period usually last? Let’s discuss the answer to this question and more.