What Is a Normal Period? Cycle Length, Flow, Pain and Red Flags
How long should a period last? How heavy is too heavy? A clear guide to normal menstrual cycles, period pain, and the changes that mean you should see a doctor.
Medically reviewed by Doctoright Medical Review Panel · Written by Doctoright Editorial Team
Updated on · 3 min read
Key takeaways
- A normal menstrual cycle is 21 to 35 days in adults (up to 45 days in the first years after periods start), with bleeding for 2 to 7 days.
- Changing a pad or tampon every hour or two, passing clots larger than a ₹5 coin, or bleeding longer than 7 days may mean heavy bleeding.
- Mild cramps in the first day or two are common; pain that stops you from daily activities isn't something you have to live with.
- Missed, very irregular or very painful periods can point to PCOS, thyroid problems, anaemia or endometriosis: see a doctor.
Every body is different, so "normal" periods cover a fairly wide range. Knowing that range helps you notice when something changes, and when it's worth talking to a doctor.
The menstrual cycle in brief
Your cycle is counted from the first day of one period to the first day of the next. Each month, hormones prepare the lining of the uterus for a possible pregnancy and one ovary releases an egg (ovulation). If pregnancy doesn't happen, hormone levels fall and the lining sheds as your period.
What's normal?
| Feature | Typical range |
|---|---|
| Age periods start | 10 to 15 years (average around 12 to 13) |
| Cycle length | 21 to 35 days in adults; 21 to 45 days in the first few years |
| Days of bleeding | 2 to 7 days |
| Total blood loss | About 30 to 40 ml (2 to 3 tablespoons); more than 80 ml is heavy |
| Variation | Cycle length can vary by a few days from month to month |
It's also common for cycles to be irregular in the first 2 to 3 years after periods begin and in the years before menopause.
How heavy is too heavy?
You may have heavy menstrual bleeding if you:
- soak through a pad or tampon every 1 to 2 hours for several hours in a row
- need to double up on protection or change at night
- pass clots larger than a ₹5 coin
- bleed for more than 7 days
- feel tired, breathless or dizzy (signs of anaemia, which is very common in Indian women)
Heavy periods can be caused by fibroids, polyps, thyroid problems, bleeding disorders or hormonal imbalance, and they're treatable.
Period pain
Cramping in the lower belly, back or thighs in the first 1 to 3 days is common. It's caused by prostaglandins, chemicals that make the uterus contract.
What helps:
- a hot water bag on your belly or back
- gentle exercise, stretching or yoga
- an anti inflammatory painkiller such as ibuprofen or mefenamic acid, taken with food at the first sign of pain (check with a doctor if you have asthma, stomach ulcers or kidney problems)
Pain that's severe, gets worse over time, starts before your period or comes with pain during sex may signal endometriosis or adenomyosis. You deserve an evaluation.
Changes to watch for
See a doctor if:
- your periods haven't started by age 15
- you miss three or more periods in a row and aren't pregnant
- cycles are shorter than 21 or longer than 35 to 45 days
- you bleed between periods or after sex
- you bleed after menopause (12 months without a period)
- pain stops you from going to school, college or work
Irregular cycles with acne, excess hair growth and weight gain may point to PCOS.
Track your cycle
Noting your start dates, flow and symptoms helps you and your doctor spot patterns. Try our ovulation and period calculator to predict your next period.
Choosing period products
Pads, tampons and menstrual cups all work well: the best choice depends on your comfort and lifestyle. Compare them in pads vs tampons vs menstrual cups, and read our tips on period hygiene.
How we reviewed this article: 3 sources
Doctoright has strict sourcing guidelines and relies on peer reviewed studies, academic research institutions and medical associations. Learn more.
- American College of Obstetricians and Gynecologists. Heavy menstrual bleeding (FAQ).
- NHS. Periods.
- American College of Obstetricians and Gynecologists. Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Committee Opinion 651.
Last medically reviewed on 6 October 2026. Originally published 8 August 2026.