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How much period blood is normal?

How much period blood is considered heavy menstrual bleeding?

Top things to know:

  • Heavy menstrual bleeding is excessive menstrual blood loss that interferes with a person’s quality of life

  • Different birth control methods may affect the heaviness of your period

  • Needing to change a pad or tampon every hour or two suggests you’re losing more blood than expected

Your period is the shedding of the endometrium (the lining of the uterus) that grows each cycle to support a potential pregnancy. The first day of your period is the first day of your menstrual cycle.

Your period can be an important indicator of your health. It’s important to know what’s “normal” or typical for you. That means how often your period happens, how light or heavy it is, and how long it lasts.


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Changes to your period

Periods can fluctuate for a while after they first start (menarche), after pregnancy, or as they come to an end (perimenopause). Not ovulating regularly — anovulation — is common during these times, and is a common cause of temporarily absent or heavy menstrual periods (1,2). If you don’t ovulate each cycle — you may miss a period, or it may come later than usual, and/or be heavier or lighter and/or shorter or longer than your usual period (1).

In between these life stages, your period should generally be about the same length and volume each cycle. You may still notice some changes  though—the heaviness and length of your period depends on your hormones, which can fluctuate. Hormones can change temporarily because of things like stress, exercise, diet, or taking an emergency contraception pill (the morning-after pill) (3, 4, 5). Every period is different, just as every body is different.

Periods and uterine bleeding can also fluctuate because of certain health conditions, like uterine polyps, fibroids, or PCOS — conditions that should be addressed with your healthcare provider. Certain bleeding conditions, medications, and infections can also affect menstrual bleeding, and cause unpredictable spotting (6).

Hormonal contraception can also affect your bleeding pattern.

How much bleeding is considered heavy menstrual bleeding (HMB)?

Heavy menstrual bleeding is a set of symptoms collectively known as abnormal uterine bleeding. Healthcare professionals and researchers have previously defined HMB as the loss of more than 80 mL of blood in one menstrual period (7). However, this is difficult to measure (8). Additionally, this definition didn’t take into account people’s perceptions and experiences, such as difficulties containing the blood flow (leaks), the impact on quality of life, or the impact of flow on daily living (2,9).

If you’re experiencing dizziness, fainting, lack energy, are short of breath, or your bleeding is so heavy that it keeps you from doing the things you normally do, such as going to work or school, then you may have heavy menstrual bleeding (10).

If you’re repeatedly soaking through a tampon or pad every one to two hours, this is considered heavy menstrual bleeding and should be brought to your healthcare provider’s attention (9).

In essence, heavy menstrual bleeding is not defined by a healthcare provider but by you, if the volume of your periods adversely impacts the activities and quality of your daily life (11). 

What is the typical period volume for people not on hormonal birth control?

Adult period volume

A typical menstrual cycle length for an adult who is not using any form of hormonal contraception is usually between 24–38 days (12), with typical period bleeding lasting up to eight days (13). Across the length of your period, it’s typical for between 5–80 ml (that’s up to 6 tablespoons) of menstrual fluid to leave your body (12).

The heaviest days of menstruation are usually at the beginning of the menstrual cycle (around the first and second day) (12). During the heaviest days of your menstrual cycle, you may notice clumps or clots in your menstrual fluid—this is common. If you have clots larger than about an inch or 25 mm long, it's a good idea to talk with your healthcare provider (10).

The color of your menstrual fluid may also change as you progress through your period, with bright red blood being more common as flow is heavy, and darker shades when your flow approaches the end of your period.

Adolescent period volume

The amount, length, and frequency of periods around the time of menarche can vary greatly. It’s common for cycles to be somewhat unpredictable for a few years after your first period. As you progress through adolescence, the amount of blood and cycles become more regular, but may still be somewhat variable (2,14).

Adolescent periods can also be up to 80 mL per period, like the adult range, but are often lighter (2).

What is the typical “period” volume for people on hormonal birth control (e.g., the pill, the ring, the patch, an IUD)?

Hormonal birth control (HBC) options like the pill, vaginal ring, hormonal IUD, or patch control the release and regulation of hormones like estrogen and progesterone within your body. When used correctly, the hormones in HBC prevent your ovaries from preparing and releasing eggs (ovulation).

Your period will change depending on the type of HBC you use. Bleeding typically happens during your “no hormone” days (when you take placebo pills, or the times in between new rings or patches). For the hormonal IUD, you may also experience unpredictable bleeding or light bleeding, and some people don’t bleed at all (15,16,17).  The bleeding you experience while using hormonal birth control is called withdrawal bleeding, and is not considered a menstrual period. Withdrawal bleeding is caused by the decline in reproductive hormones in your body during days when you get low or no hormones from your pill, patch, or ring (12,18).

Many people experience lighter bleeding, and some don’t bleed at all while using hormonal birth control (19). When affected by hormonal birth control, the lining of your uterus doesn't thicken as much as it does without hormonal birth control. This typically results in lighter, shorter, or occasionally absent “periods”, especially for people who have been using hormonal birth control for many months or years.

If you are using a Copper IUD, which is non-hormonal, you will experience the same fluctuations of estrogen and progesterone across your cycle as you did when you weren’t using a copper IUD. Many people experience an increased amount of menstrual flow and longer period length while using the copper IUD, especially in the first 6–12 months (15, 20). This may happen due to vascular changes and changes to blood flow in the uterus (17,21,22,23). 


Spotting is defined as any bloody vaginal discharge with a volume not large enough to require the use of period products (i.e., you don’t need to use a pad or a tampon) (12).  Generally, if you have light bleeding that occurs at the beginning of your period, you should consider that part of your period, not spotting. However, if it’s very, very light—you only see a little on your toilet paper—that would be considered spotting.

Spotting can be caused by a variety of reasons, including hormonal birth control (HBC), ovulation, or other physiological reasons (3,19,12). Spotting that is not before or after your period bleeding, or unexplained spotting while using HBC, should be discussed with a healthcare provider. Spotting is common in the first weeks of pregnancy, but heavier bleeding is a reason to speak to your healthcare provider. Spotting can also be caused by certain infections and physical changes, which should also be addressed with a healthcare provider (6,24,25).

When should you seek help from your healthcare provider about your period bleeding?

You should speak to your healthcare provider if (9, 10, 13, 14):

  • You have periods that last more than eight days

  • You need to change your tampon or pad more than every one or two hours

  • You need to double up on period products because of heavy bleeding (e.g., you have to wear a tampon and pad at the same time)

  • You have a menstrual flow with blood clots the size of a quarter/€1 coin (1 inch/25 mm) or larger

  • You have a menstrual flow so heavy that it keeps you from doing the things you would normally do, such as going to work or school

  • You’re dizzy, faint, lack energy, or are short of breath

Excessive menstrual bleeding can impact a person’s quality of life and can cause iron deficiency anemia (26,27,1). Heavy menstrual bleeding can have many potential causes including fibroids (growth of muscle tissue on your uterus), adenomyosis (a condition where endometrial tissue invades the muscular wall of the uterus), bleeding disorders  (like Thrombocytopenia or Von Willebrand disease), uterine polyps (growths on the inside of your uterus), and (rarely) tumors (28,29)

If your period has stopped and you are not taking any form of hormonal contraceptive, you should also discuss this with your healthcare provider.

Everybody is different, just as everyone's period is different. It’s important to know what is typical for you, so you can monitor any changes around your period.  Tracking with Clue can help you see how your menstrual cycle typically looks for you. Speak to your healthcare provider if you are concerned about your period volume.


  • How much blood do you lose on your period in cups?

This varies from person to person, but during a typical period, you may lose between 5-80 mL, which is up to 6 tablespoons of blood (12), or one and a half shot glasses. 

  • Is 400 ml of blood lost during your period a lot?

Everybody is different, but the ‘typical’ amount of blood lost during your period is between 5-80 mL. 400 mL is considered a lot of blood to lose during your period. 

  • How much blood does a sanitary pad hold?

This depends on the brand of period pad that you use. A saturated Kotex nighttime pad may hold 15 mL of blood while a daytime Kotex pad may hold 5 ml (30).

  • Why is my period so heavy and clotty?

Clots stop bleeding during menstruation that comes from blood vessels (31). You may have an underlying medical condition causing heavy menstruation if you see many large blood clots (31). If so, you should speak to a healthcare provider.

  • How much period blood do we lose a day?

Some people notice heavier bleeding during the first few days (32). During a typical period, you may lose between 5-80 mL of blood in total (12).

Article was originally published 29 May 2018.

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