How much blood do you lose on your period?
Most people lose about 20 to 90 ml of blood over a whole period, roughly 1 to 5 tablespoons, according to the NHS. It feels like more because period fluid also contains tissue and mucus. Bleeding is heaviest in the first 2 days. Losing more than about 80 ml, or soaking through protection every hour or two, counts as heavy.
Why it looks like more
Period fluid isn't just blood. It's a mix of blood, uterine lining, cervical mucus and vaginal fluid, so the total volume is bigger than the blood alone. Spread across pads or underwear, a few tablespoons can look like a lot.
How to estimate your own flow
| Product | Roughly holds when full |
|---|---|
| Light tampon or pad | Up to about 3 to 6 ml |
| Regular tampon or pad | About 6 to 9 ml |
| Super tampon or heavy pad | About 9 to 15 ml |
| Menstrual cup (small to large) | Often 15 to 30 ml or more; many have markings |
Capacities vary by brand, so treat these as rough guides. A cup with measurement lines is the easiest way to see your actual flow. If you're filling a regular product every few hours on your heaviest days, you're probably in the normal range.
Normal vs heavy
- Normal: about 20 to 90 ml over 2 to 7 days, heaviest on days 1 and 2.
- Heavy (research definition): more than 80 ml per period.
- Heavy (in real life): soaking a pad or tampon every 1 to 2 hours for several hours, needing double protection or night changes, clots the size of a quarter or bigger, or bleeding for more than 7 days.
- The NICE view: doctors now focus on whether bleeding affects your quality of life, not just the number of ml.
Check yours with what counts as a heavy period, and read why is my period so heavy for causes.
Blood loss, energy and mood
Over months, heavier periods can lower your iron stores. Low iron causes tiredness, poor concentration, breathlessness and low mood, which can make period week feel even harder. If you're always wiped out on your period, it's worth asking for a blood test. See why am I so tired on my period.
See a doctor if you soak through protection every 1 to 2 hours, pass large clots, bleed for more than 7 days, or feel tired, dizzy or breathless. Get urgent help if you soak a pad an hour for more than 2 hours, feel faint, or could be pregnant and are bleeding heavily.
Frequently asked questions
Is losing a cup of blood on your period normal?
No. A cup is about 240 ml, far more than a normal period. If you think you're losing that much, see a doctor.
How many tampons a day is normal?
Usually 3 to 6 on heavier days. Change at least every 4 to 8 hours. Needing one every 1 to 2 hours is heavy.
Can you lose too much blood on your period?
Yes. Very heavy bleeding can cause anemia, and rarely an emergency. Soaking a pad an hour for several hours needs urgent advice.
Does period blood loss make you lose weight?
No. The amount of blood is small, and any weight change around your period is mostly fluid.
Sources
- NHS: Periods
- NICE guideline NG88: Heavy menstrual bleeding: assessment and management
- ACOG: Heavy Menstrual Bleeding
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
What counts as a heavy period?What is a heavy period? Soaking a pad or tampon every 1 to 2 hours, clots bigger than a quarter, or bleeding over 7 days. A quick self-check.Why is my period so heavy? Common causes and what helpsWhy is my period so heavy? Fibroids, polyps, adenomyosis, hormone changes, an IUD or a bleeding disorder are common causes. What helps and when to get help.Heavy periods: what counts as heavy and what helpsHow to tell if you have heavy periods: soaking a pad every hour or two, clots, bleeding over 7 days. Causes, treatments that work, and when to get help.
How often should you change a tampon?How often should you change a tampon? Every 4 to 8 hours, never more than 8, per the FDA. Picking absorbency, sleeping in one, and signs of TSS to know.
Period calculator: when is my next period?Free period calculator: enter the first day of your last period and your cycle length to see your next 6 periods. Private, instant, nothing is stored.