A typical period lasts 2 to 7 days. Most people fall somewhere in the middle of that range, with 4 to 5 days being common. Anything within that window is normal, even if your period is consistently shorter or longer than a friend’s.
What Counts as a Normal Period
The bleeding itself lasts 2 to 7 days, and the full menstrual cycle (day one of your period to day one of the next) runs 21 to 35 days. Most periods produce less than 45 milliliters of blood total, which is about three tablespoons. That can feel like a lot more because menstrual fluid also contains tissue from the uterine lining, but the actual blood loss is relatively small.
Bleeding that exceeds 80 milliliters (roughly five and a half tablespoons) per cycle is considered heavy. A practical way to gauge this: if you’re soaking through a pad or tampon every one to two hours for several hours in a row, that’s unusually heavy flow.
How Your Period Changes With Age
Periods don’t stay the same throughout your life. In the first few years after your first period, cycles tend to be longer and less predictable. People under 20 have cycles averaging about 30 days, and their cycle length can swing by more than 5 days from month to month. This irregularity comes from a still-maturing reproductive system, and cycles generally settle into a more regular pattern within about four years.
Through your 20s and 30s, cycles typically become their most consistent, averaging around 28 to 29 days. Then in your early to mid-40s, things shift again. Cycles often get slightly shorter at first, averaging about 28 days, but they also become more unpredictable. After age 45, that variability ramps up significantly. People over 50 see their cycle length swing by an average of 11 days from one month to the next. Eventually, after one to three years of increasingly long and irregular cycles, menstruation stops permanently. The average age for menopause in the U.S. is around 52.
Why Some Periods Last Longer Than 7 Days
If your period regularly stretches past a week, something is usually driving that. The most common culprits fall into two categories: structural issues in the uterus and hormonal imbalances.
Uterine fibroids are noncancerous growths in the muscle wall of the uterus. They’re extremely common during the reproductive years and can cause periods that are both heavier and longer than usual. Polyps, which are small growths on the uterine lining, have a similar effect. Adenomyosis, a condition where the tissue that normally lines the uterus grows into the muscular wall, also tends to produce prolonged, heavy bleeding.
On the hormonal side, conditions like polycystic ovary syndrome (PCOS), thyroid disorders, obesity, and insulin resistance can all throw off the balance of hormones that regulate your cycle. When that balance is disrupted, the uterine lining can build up too thick and shed irregularly, leading to extended or unpredictable bleeding. Sometimes the ovaries simply don’t release an egg during a given cycle, which also disrupts the normal hormonal signals that tell the lining when and how to shed.
How Birth Control Affects Period Length
Hormonal contraceptives are one of the biggest factors that can change how long you bleed, and in many cases they shorten or eliminate periods entirely.
Extended-cycle birth control pills work on a 91-day schedule: 84 days of active pills followed by one week of inactive or very-low-dose pills. The result is a period roughly once every three months. Continuous-use pills skip the inactive week altogether, meaning no scheduled period at all.
Hormonal IUDs gradually reduce both the frequency and duration of periods over time. One year after getting a higher-dose hormonal IUD, about 20% of users report having no period at all. By two years, that number climbs to 30 to 50%.
The hormonal injection follows a similar pattern. After one year of use, 50 to 75% of people on the injection stop having periods entirely, and the likelihood of period-free months increases the longer you use it. The vaginal ring and the birth control patch can also be used continuously (without the scheduled break week) to suppress periods, though this is something to discuss with a provider since the approach varies by product.
Signs Your Period Length Isn’t Normal
A period that lasts more than 7 days is worth getting evaluated. The same goes for any of these patterns:
- Soaking through protection fast. Needing to change a pad or tampon more than once every one to two hours signals unusually heavy flow.
- Cycles shorter than 21 days or longer than 45 days. Either extreme suggests something is off with ovulation or hormonal regulation.
- A gap of 90 days or more between periods, even if it only happens once.
- Periods that were regular and then became irregular. A change in an established pattern matters more than having always been slightly unpredictable.
- Dizziness or faintness during your period. This can indicate enough blood loss to affect your iron levels or blood volume.
If you have a personal or family history of blood clotting problems, that’s also relevant. Clotting disorders can make periods significantly heavier and are worth screening for, since they’re treatable once identified.