Labs & Reports · CBC & blood counts

Hemoglobin Normal Range: Levels by Age and Sex, Low and High Hb

On most Indian reports a normal hemoglobin runs 13 to 17 g/dL for a man and 12 to 15 for a woman.¹ Under the WHO's 2024 definition, anemia begins under 13 g/dL for men and under 12 for non-pregnant women, with lower cut-offs in pregnancy and in children.² Your lab prints its own interval, and that is the one your result is read against. Check it before you read anything else here.

Hemoglobin is the number on a CBC that decides whether you are anemic. Everything else on the red cell side, the RBC count, the hematocrit, the indices, tells the doctor why. Which means you can read your report in a fixed order, and this page walks it. This page covers the normal range by age, sex and pregnancy, what a low result means, and the reasons it drops. Raising a low level has its own page.

What is hemoglobin, and what is the normal range? Copy link

Hemoglobin (Hb, sometimes printed as HGB or "Hb gm%") is the iron-carrying protein packed inside each red cell; it picks up oxygen in the lungs and lets it go everywhere else. The test measures how many grams of it sit in a deciliter of blood. It is printed as a single line inside the CBC, the complete blood count; Indian labs also order it on its own as "haemoglobin estimation" or a hemoglobin count, and there is no separate "Hb blood test normal range" for those. Normal hemoglobin levels are the table below.

Some reports print grams per liter instead: 130 g/L is 13.0 g/dL. An "L" flag means below your lab's floor: a reason to read the next lines, seldom an emergency. The symptoms that cannot wait are listed under when to seek care.

Normal hemoglobin level in female adults

Outside pregnancy, 12 to 15 g/dL is the usual printed range for a woman, and 12.0 is where the WHO draws the anemia line for ages 15 to 65.² That floor is the one that matters most in India, because, as you probably know, this is the group the numbers are worst for: NFHS-5, the national survey, put 57% of women between 15 and 49 in the anemic band.³ As you might expect, adult women normally run lower than men largely because sex hormones influence red-cell production, about 12% lower on average in health; menstruation separately increases the risk of iron deficiency through recurrent blood loss.¹⁴ Heavy periods, soaking a pad in an hour or passing clots larger than a coin, are the commonest slow leak behind a hemoglobin that keeps drifting down.⁴

Hemoglobin level for men

Men run 13 to 17 g/dL, with anemia below 13.0.^{1, 2} The adult male range runs higher largely because androgens such as testosterone stimulate red-cell production.¹⁴ That higher floor changes what a low result means for you. A man at 11.5 has fewer places to lose blood from than a woman, so the same number earns a harder look: once iron deficiency is confirmed in a man, or a woman after menopause, the gut is checked for a source before anyone blames diet.⁴ One Indian man in four between 15 and 49 is anemic all the same.³

Hemoglobin normal range by age

Children run lower than adults, and the cut-offs step up with age, so do not read a child's report against the adult table. Under the 2024 WHO guideline, anemia begins below 10.5 g/dL from 6 to 23 months, below 11.0 from 2 to 4 years, below 11.5 from 5 to 11, and below 12.0 from 12 to 14 for both boys and girls; from 15 the adult cut-offs apply.² The 6-to-23-month cut-off is the one the 2024 revision lowered, by half a gram, because healthy toddlers simply run lower than the old rule assumed.² Newborns are the exception at the top, and a surprising one: they are born with hemoglobin well above adult levels and drift down over the first months, so a paediatric report prints its own age-specific interval.

At the other end, nothing obliges the number to fall as you get older. In the Chennai reference group, men past 45 averaged 14.8 g/dL against 14.1 for younger men, and women past 45 averaged 12.35 against 12.01.¹ The WHO 2024 table covers adults only through age 65; evidence was insufficient to establish a separate cutoff beyond that age.² Which means a new low hemoglobin in your father or mother should be interpreted against the laboratory range, previous results, symptoms and clinical context, and never dismissed as "just age".

Hemoglobin in pregnancy

If you are pregnant, expect the number to drop, and expect that to be fine. From about week 6 the plasma starts to expand, by a tenth to a sixth before week 12, and by term the circulation holds roughly a liter and a half more than it did, so a hemoglobin that has not changed at all reads lower per deciliter.⁵ The WHO's cut-offs allow for that: in pregnancy anemia begins at 11.0 g/dL during trimesters one and three, and at 10.5 in the second, when the dilution is at its greatest.² Two cautions travel with the lower bar. Dilution and true iron deficiency can coexist, so a low result still gets a ferritin. And the antenatal clinic's daily iron and folic acid is prevention, which carries on regardless of the result.⁶ More than half of pregnant women in India are anemic by the survey's count.³

Healthy Indians who sit below the printed floor Copy link

A Chennai hospital went back through 2,443 health-check files from 2011 and kept the 500 people, half men and half women, whose records showed no anemia, diabetes or chronic disease. Against the textbook hemoglobin range on their own reports, 20.2% of those men and 41.5% of those women fell outside it, nearly all on the low side.¹ The women's 2.5th percentile came out at 9.22 g/dL, nearly three grams under the 12.0 floor.

Hold that figure with its caveats, because it is easy to over-read. One city, one year, one hospital's paying clientele; "healthy" meant nothing on the chart, and the authors' own explanation for the low tail was nutritional deficiency and worm infestation in the local population.¹ The WHO looked at exactly this question in 2024, whether cut-offs should be adjusted for genetic ancestry, and decided against it for lack of evidence, while it did add adjustments for altitude and smoking.² So a woman at 11.4, flagged L, is in the company of a great many healthy-looking Indian women. Of course, being common does not make it fine, and a ferritin is what tells the two apart. Reassurance does not count. That is the reason the survey's 57% is a public-health emergency and not a rounding error.

Low hemoglobin: meaning, and what happens if hemoglobin is low Copy link

A hemoglobin below your lab's floor, or below the WHO cut-off for your group, is anemia. The word describes the number and stops there; the cause is your next question. The first thing most people feel is effort: stairs that used to be nothing, a heaviness in the afternoon that sleep does not clear, breathlessness on a walk you have done a hundred times. Pale nail beds, a pink-white inner lower eyelid, a pounding heartbeat on exertion, cold hands, and a craving to chew ice (a sign of iron deficiency specifically) are what a doctor looks for. Not one of these is specific to anemia, and at a mild level most people feel nothing at all, which is why the survey finds anemia in people who never went looking for it.

How low is dangerous for you? There is no fixed number, because the body adapts to a slow fall and is overwhelmed by a fast one. A woman who has drifted to 8 g/dL over a year of heavy periods may be working and climbing stairs; a man who has bled to 8 in a day is in trouble. The one hard threshold in the literature is for hospital transfusion, and it sits lower than most people expect. The 2023 AABB guideline recommends a restrictive transfusion strategy: in most hemodynamically stable hospitalized adults, transfusion is considered when hemoglobin falls below 7 g/dL; clinicians may use an 8 g/dL threshold after orthopedic surgery or in people with pre-existing cardiovascular disease. Symptoms and the wider clinical picture still matter.⁷ Outside hospital, urgency depends on how fast the number fell and on symptoms: chest pain, breathlessness while sitting, a faint, new weakness, or bleeding that is still going.

Mild, moderate and severe anemia

Laboratories and doctors grade anemia in three bands, and the band you land in changes what happens next. For a non-pregnant woman, mild is 11.0 to 11.9 g/dL, moderate 8.0 to 10.9, and severe below 8.0; for a man, mild is 11.0 to 12.9, moderate 8.0 to 10.9, severe below 8.0. In pregnancy the bands sit lower: mild 10.0 to 10.9, moderate 7.0 to 9.9, severe below 7.0, and in the second trimester mild runs 9.5 to 10.4.² Mild anemia is investigated and treated in the clinic on the same timetable as the cause; you will not be admitted for it. Moderate anemia usually means a proper work-up before treatment starts, so the tablets match the deficiency. Severe anemia is a same-week conversation, and with symptoms, a same-day one.

Reasons for low hemoglobin: what causes a low blood count Copy link

Think of it, as your doctor does, as four questions asked at once: is the marrow making enough, is blood leaving somewhere, are red cells being broken down early, and is the sample diluted? Two can be true together. In India the answer to the first is usually iron, and to the second, periods or the gut.

• Iron deficiency. Iron is the centre of the heme ring; without it the marrow builds cells that are small, pale and short of hemoglobin. The ferritin level tells you whether the stores are empty, but inflammation pushes ferritin up, so an infected or arthritic person can be iron-deficient with a ferritin that reads normal; transferrin saturation and a CRP break the tie. Serum iron by itself proves nothing.⁴
• Blood loss. Periods, piles, an ulcer, a polyp, a gut that oozes a few millilitres a day for years. Tarry black stools mean the bleed is high up and old; mention them. In men and in women after menopause, proven iron deficiency is treated as a gut problem until the gut is checked.⁴
• Vitamin B12 or folate deficiency. The vegetarian household's deficiency, and the one metformin and acid-suppressing tablets cause over years. Cells come out large and few. B12 deficiency can cause neurological symptoms even when anemia or macrocytosis is absent. Pins and needles, numbness, balance problems or gait changes deserve prompt assessment because delayed treatment can leave persistent neurological deficits.⁸
• Kidney disease. Failing kidneys make less erythropoietin, the hormone the marrow needs to keep producing, and hemoglobin drifts down as kidney function does; the KDIGO guideline treats anemia as a standard part of kidney care.⁹ A raised creatinine on the same page is the link; the kidney function decoder reads that line.
• Long-running inflammation or infection. TB, rheumatoid arthritis, an abscess nobody found. The body hides its iron from the marrow to starve the infection, and the hemoglobin pays, with a ferritin that looks fine.⁴
• Thalassemia trait. Roughly one Indian in 25 carries it unknowingly, and in some communities it is closer to one in ten.¹⁰ Hemoglobin sits mildly low for life, the cells are small, and iron tablets do not move it because iron was never the problem, though the two can coexist. The giveaway on the CBC is a high RBC count next to a low hemoglobin, and hemoglobin electrophoresis or HPLC confirms it.
• Hypothyroidism. Low thyroid hormone slows the marrow along with everything else, and a mild anemia is a recognized companion. A raised TSH on the same day's tests may explain both.
• Pregnancy, or fluids. Dilution. Expected in pregnancy and after a drip, and only accepted as the whole explanation once a ferritin agrees.⁵
• Hemolysis, marrow disease, chemotherapy and a handful of other medicines. Uncommon, and it is the reticulocyte count and the blood film, ordered when the first round finds nothing, that catch them.

What is not on that list, and people expect it to be, is "weakness" or "not eating properly". Food only lowers hemoglobin when it has left out iron, B12 or folate month after month, and the fix is to find out which one, which takes one more test. Skipping that step and reaching for iron tablets, which happens more than you would think, is how a thalassemia carrier spends years being treated for anemia, and how an ulcer keeps bleeding while the tablets hide it.

High hemoglobin: what causes it Copy link

A hemoglobin above range is less common and, frankly, in most people it means less plasma, with no extra red cells at all. Vomiting, a bout of diarrhoea, a fast through a hot day, or simply a sample drawn before your first glass of water will do it: the whole red-cell panel climbs together and comes back down once you are rehydrated.¹¹ Smokers run higher because carbon monoxide occupies part of their hemoglobin and the marrow makes more to compensate; a large American survey put the difference at about 0.4 g/dL, larger in heavier smokers, and the WHO's 2024 guideline now subtracts a smoking adjustment from a measured hemoglobin before applying its cut-off.^{2, 12} Altitude raises your hemoglobin as the body adapts to lower oxygen. For diagnosing anemia in people living at elevation, WHO recommends subtracting 0.4 g/dL from measured hemoglobin at 500–999 m, 1.8 g/dL at 2,500–2,999 m and 2.5 g/dL at 3,500–3,999 m. Leh sits at roughly 3,500 m, so, if you live there, it belongs in the last of those bands. These are residence-based anemia adjustments, and no rule says they apply automatically after a short trip.² Untreated sleep apnea, chronic lung disease, and injections of testosterone or erythropoietin raise it the same way.¹¹

The rare cause is polycythemia vera, a marrow disorder that keeps producing red cells whether or not the body asks for them. It is investigated when hemoglobin stays over 16.5 g/dL in a man or 16 in a woman, or the hematocrit sits above 49% or 48%, and nothing else explains it; a JAK2 mutation test and, when required, marrow findings settle the diagnosis under the 2022 WHO classification.¹³ A high reading in someone who was dry, smokes, or has just returned from the hills gets repeated on an ordinary day before it gets investigated. Donating blood to bring it down, or starting aspirin, is not a treatment for a number.

Reading your own result Copy link

1. Unit and interval first. g/dL or g/L (divide by ten), and a reference group that matches your age, sex and pregnancy status. HbA1c, sometimes printed as "glycosylated hemoglobin", is a different test for blood sugar; its decoder is the HbA1c test guide. HbA0 and HbA2 on an HPLC report are hemoglobin types from a thalassemia screen, not levels.
2. Grade it. Mild, moderate or severe against the bands above. That sets your pace.
3. Then MCV. Small cells send you toward iron or thalassemia trait, large cells toward B12 or folate, normal-sized cells toward bleeding, kidneys, inflammation or thyroid. To split iron deficiency from trait, look at the RBC count beside the hemoglobin.
4. Then one test, singular. Depending on the MCV and clinical context, ferritin is often the first additional test; other patterns may call for B12, a reticulocyte count, a film or kidney testing. Nobody needs the forty-test package to explain one low line.

Ferritin and B12 are not part of a CBC. If the CBC arrived inside a full body checkup, look down the list, because most packages run ferritin or an iron panel on the same tube and the answer may already be printed two pages later. The other lines of the CBC are explained on the CBC test guide; the remaining test decoders sit under Labs & Reports. One thing people rarely check, and should: how the number was measured. a finger-prick reading on a portable meter runs a little different from a venous sample on a lab analyzer, so two results from two methods are not a trend.²

When to seek care