A good hemoglobin level for adult men falls between 14.0 and 17.5 grams per deciliter (g/dL), while for adult women the normal range is 12.3 to 15.3 g/dL. These ranges shift depending on age, pregnancy, and even where you live, so a number that looks low for one person can be perfectly healthy for another.
Normal Ranges for Adults
Hemoglobin is the protein inside red blood cells that carries oxygen from your lungs to every tissue in your body. When your doctor orders a complete blood count, hemoglobin is one of the key numbers on the report, measured in grams per deciliter of blood.
For adult men, 14.0 to 17.5 g/dL is considered normal. For adult women, the range is 12.3 to 15.3 g/dL. The difference is largely driven by hormones: testosterone stimulates red blood cell production, which is why men typically run higher. If your result lands anywhere within the range for your sex, that’s a good hemoglobin level with no further action needed.
Normal Ranges for Children
Children’s hemoglobin levels change dramatically in the first few years of life. Newborns start high, around 16.5 g/dL on average, because they carry extra red blood cells from the womb. By two months that number dips to roughly 11.2 g/dL as the body breaks down the excess cells and begins producing its own at a steadier rate.
From six months to two years, a normal average is about 12.0 g/dL, climbing gradually to 12.5 g/dL between ages two and six, then 13.5 g/dL between ages six and twelve. Once puberty begins, boys and girls diverge. Adolescent males average around 14.5 g/dL, while adolescent females average about 14.0 g/dL, with the gap widening into adulthood.
How Pregnancy Changes the Numbers
During pregnancy, your blood volume increases by 40 to 50 percent, but red blood cell production only rises by 15 to 25 percent. That mismatch dilutes the hemoglobin concentration in your blood, so levels that would be flagged as low outside of pregnancy are completely expected while you’re carrying a baby.
Doctors use adjusted thresholds to define anemia during pregnancy. In the first trimester, hemoglobin below 11 g/dL is considered low. In the second trimester, the cutoff drops to 10.5 g/dL because dilution peaks. By the third trimester, the threshold returns to 11 g/dL. If your levels stay above these numbers, your hemoglobin is in a healthy range for pregnancy.
When Hemoglobin Is Too Low
Hemoglobin below the normal range means anemia, and the symptoms tend to creep in gradually. You might notice fatigue, shortness of breath during activities that used to feel easy, pale skin, dizziness, or cold hands and feet. Mild anemia often produces no obvious symptoms at all, which is why it’s usually caught on routine blood work rather than from a specific complaint.
Iron deficiency is the most common cause worldwide. Women of reproductive age are especially vulnerable because of monthly blood loss from menstruation. Other causes include vitamin B12 or folate deficiency, chronic kidney disease, inflammatory conditions, and blood loss from the digestive tract that you may not even notice.
At the severe end, hemoglobin below 7 to 8 g/dL is the threshold where doctors typically consider a blood transfusion. Large clinical trials involving over 21,000 patients have shown that transfusing at this level is just as safe as transfusing at a more generous 9 to 10 g/dL threshold. In practice, the decision also depends on symptoms and whether you have heart disease or other conditions that make your body less tolerant of low oxygen delivery.
When Hemoglobin Is Too High
Hemoglobin above 16.5 g/dL in men or above 16.0 g/dL in women is considered elevated. In children, the cutoff is about 16.6 g/dL, and in infants it’s 18 g/dL. High hemoglobin thickens the blood, which can increase the risk of clots, stroke, or heart attack.
The most common everyday causes are dehydration (which concentrates the blood temporarily), smoking (carbon monoxide from cigarettes triggers extra red blood cell production), and living at high altitude. At elevation, thinner air contains less oxygen, so the body compensates by making more red blood cells. Research on workers at high altitude found hemoglobin increased by roughly 0.05 g/dL for every consecutive year spent at elevation. Less common causes include bone marrow disorders and the use of performance-enhancing drugs like anabolic steroids.
Hemoglobin vs. Hemoglobin A1c
If you’ve seen “hemoglobin A1c” on lab results and wondered whether it’s the same thing, it’s not. Standard hemoglobin measures how much oxygen-carrying protein is in your blood. Hemoglobin A1c measures the percentage of that protein that has glucose (sugar) stuck to it, which reflects your average blood sugar over the past two to three months. Red blood cells live about three months, so glucose accumulates on hemoglobin for their entire lifespan, giving doctors a longer-term picture than a single blood sugar reading. A1c is a diabetes screening and monitoring tool, not a measure of red blood cell health.
How to Support Healthy Hemoglobin
Iron is the essential building block for hemoglobin, and how much you need each day depends on your age and sex. Adult men and women over 51 need about 8 mg daily. Women between 19 and 50 need 18 mg because of menstrual losses, and pregnant women need 27 mg, the highest requirement of any group.
Iron from animal sources (lean meat, seafood, poultry) is absorbed more efficiently than iron from plants. Plant-based sources like beans, lentils, nuts, fortified cereals, and dark leafy greens still contribute meaningfully, but the body absorbs that form of iron at a lower rate. If you eat a fully vegetarian or vegan diet, your iron requirement is roughly 1.8 times higher than someone who eats meat. Pairing plant-based iron with vitamin C (citrus, bell peppers, tomatoes) helps boost absorption.
Some foods actually block iron absorption. Spinach, despite its reputation, contains compounds that reduce how much iron your body can use. Coffee and tea have a similar effect when consumed with meals. Spacing these out from iron-rich foods or supplements can make a noticeable difference if you’re working to bring a low level back up.
Beyond iron, your body also needs vitamin B12 and folate to produce healthy red blood cells. B12 comes primarily from animal products and fortified foods, while folate is abundant in leafy greens, citrus fruits, and legumes. If your hemoglobin is low and your iron intake seems adequate, a deficiency in one of these vitamins could be the missing piece.