A typical period lasts between 2 and 7 days, with most people bleeding for about 5 days. The full menstrual cycle, from the first day of one period to the first day of the next, runs 21 to 35 days. Both the length of bleeding and the overall cycle vary from person to person, and your own pattern can shift across different life stages.
What Counts as a Normal Period Length
The 2-to-7-day window is wide because “normal” really depends on your body. Some people consistently bleed for 3 days and feel done; others reliably go 6 or 7. What matters most is consistency. If your period has always been on the shorter or longer end of that range and follows a predictable pattern, that’s your normal.
In terms of blood loss, most people lose less than 60 milliliters of blood per cycle, which is roughly 4 tablespoons. That sounds small, but menstrual fluid also contains tissue from the uterine lining and other fluids, so the total volume on your pad or tampon looks like more than it is. Blood loss above 80 milliliters per cycle is considered excessive.
How to Count Your Period Days
Day 1 is the first day of actual bleeding, not spotting. Light brown or pink discharge before your flow starts doesn’t count. You start counting when you see enough red blood that you’d reach for a pad, tampon, or cup. Your period ends on the last day of bleeding. Again, a day or two of trailing brown spotting afterward is normal and doesn’t add to your count.
Tracking for three or four consecutive cycles gives you a reliable picture of your personal pattern. Most period-tracking apps make this simple, but a calendar works just as well.
Why Period Length Changes With Age
Periods don’t stay the same across your lifetime. In the first year or two after menstruation begins, cycles are often irregular and unpredictable. The hormonal signaling system between the brain and the ovaries is still calibrating, and many teens don’t ovulate every cycle during this window. Periods may be longer, shorter, heavier, or lighter from month to month before settling into a pattern.
Through the 20s and 30s, cycles tend to be the most regular and predictable they’ll ever be. Then, starting in the mid-to-late 40s, the transition toward menopause brings another wave of irregularity. The remaining eggs produce less estrogen, and the body compensates by ramping up signals that trigger ovulation earlier. This can shorten the overall cycle to as few as 21 days. Some cycles get skipped entirely as ovulation becomes inconsistent. Periods may also become lighter or heavier during this phase before eventually stopping altogether.
When a Period Is Too Long
Bleeding that lasts more than 7 days is considered prolonged. If this happens once, it may just be an off cycle. If it happens regularly, something is usually driving it. Common causes include:
- Fibroids or polyps: noncancerous growths in or on the uterus that increase the surface area of the lining being shed
- Irregular ovulation: when you don’t ovulate in a given cycle, the uterine lining can build up thicker than usual, leading to heavier and longer bleeding when it finally sheds. This is especially common during puberty, perimenopause, and in people with PCOS or thyroid conditions.
- Adenomyosis: uterine lining tissue grows into the muscular wall of the uterus, causing prolonged, heavy periods
- Bleeding disorders: conditions that affect how well blood clots can make periods both heavier and longer
- Medications: blood thinners and aspirin can extend bleeding
- Copper IUD: this non-hormonal form of birth control can cause heavier, longer periods, particularly during the first year after insertion
In rare cases, prolonged menstrual bleeding can be an early sign of endometrial cancer, which is one reason persistent changes in your bleeding pattern are worth investigating.
When a Period Is Too Short
Periods that consistently last 2 days or less, with very light flow, fall under the category of hypomenorrhea. If your period has always been light and short since you first started menstruating, that’s likely just how your body works. It becomes worth paying attention to when a previously normal period becomes noticeably shorter or lighter for several months in a row.
Stress is one of the most common culprits. When your body produces excess cortisol, the stress hormone, it interferes with the hormonal chain reaction that builds and sheds the uterine lining. Significant weight loss has a similar effect by reducing estrogen production. An overactive thyroid disrupts communication between the brain and ovaries, making cycles both shorter and lighter. PCOS can also cause light, infrequent periods because elevated androgen levels prevent regular ovulation.
Perimenopause naturally produces lighter, shorter periods in some people as estrogen declines. And occasionally, a narrowing of the cervical opening (from prior surgery, infection, or other causes) physically limits how much blood can exit the uterus, making periods appear lighter than they actually are.
How Birth Control Affects Period Length
Hormonal birth control is one of the biggest modifiers of period length and frequency. Combination birth control pills that are taken in an extended pattern (84 active days followed by 7 inactive days) reduce periods to roughly once every three months. Some continuous-use pills eliminate periods entirely for a full year.
Hormonal IUDs gradually reduce both the frequency and duration of periods over time. After one year with a higher-dose hormonal IUD, about 20% of users stop getting periods altogether. After two years, that number climbs to 30% to 50%. Lower-dose hormonal IUDs still lighten periods but are less likely to stop them completely.
The copper IUD is the outlier. Because it contains no hormones, it doesn’t shorten periods. In fact, it tends to make them heavier and longer, especially in the first year. If you’ve recently had a copper IUD placed and your periods seem to drag on longer than they used to, that’s a well-documented side effect rather than a sign of a separate problem.
What Triggers Bleeding to Start and Stop
Your period is controlled by two hormones: estrogen and progesterone. In the first half of your cycle, estrogen rises and thickens the uterine lining in preparation for a potential pregnancy. After ovulation, progesterone takes over and stabilizes that lining. If no pregnancy occurs, both estrogen and progesterone drop sharply. That hormonal withdrawal is the signal for the lining to break down and shed, which is your period.
Bleeding stops when the lining has fully shed and the uterus repairs the exposed surface. Small blood vessels in the uterine wall constrict to slow the bleeding, and the tissue regenerates quickly. The whole process resets as estrogen begins rising again for the next cycle. When this hormonal rhythm is disrupted, whether by stress, thyroid issues, PCOS, or approaching menopause, the timing and duration of your period shift accordingly.