A healthy hemoglobin level for adult men is 13.2 to 16.6 grams per deciliter (g/dL), and for adult women it’s 11.6 to 15 g/dL. These ranges shift depending on age, pregnancy, altitude, and smoking status, so a result that looks low on paper isn’t always a problem, and one that looks normal isn’t always fine.
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 a lab measures your hemoglobin, it reports how many grams of this protein are in a deciliter of blood. The standard healthy ranges, used by most U.S. labs, are:
- Men: 13.2 to 16.6 g/dL
- Women: 11.6 to 15.0 g/dL
The gap between men and women is driven primarily by testosterone, which stimulates red blood cell production. After menopause, women’s levels often rise slightly and narrow that gap. Older adults of both sexes tend to drift toward the lower end of their range, though there isn’t a separate “elderly” reference range in most clinical guidelines.
Normal Ranges for Children
Children’s hemoglobin changes dramatically in the first year of life. Newborns arrive with very high levels because they needed extra oxygen-carrying capacity in the womb, then those levels drop sharply before climbing again through childhood. Here’s what’s typical at each stage:
- Newborn (term): average 16.5 g/dL, lower limit around 13.5
- 1 month: average 13.9 g/dL, lower limit around 10.7
- 2 months: average 11.2 g/dL, lower limit around 9.4
- 3 to 6 months: average 11.5 g/dL, lower limit around 9.5
- 6 months to 2 years: average 12.0 g/dL, lower limit around 10.5
- 2 to 6 years: average 12.5 g/dL, lower limit around 11.5
- 6 to 12 years: average 13.5 g/dL, lower limit around 11.5
Once puberty begins, the ranges split by sex. Boys ages 12 to 18 average 14.5 g/dL with a lower limit of 13.0, while girls the same age average 14.0 g/dL with a lower limit of 12.0. That dip in the two-month range is completely normal. It’s sometimes called “physiologic anemia of infancy” and resolves on its own as the baby starts producing its own red blood cells more efficiently.
What Counts as Low Hemoglobin
Falling below the lower end of the normal range is called anemia. It doesn’t always cause noticeable symptoms. Mild anemia, where hemoglobin is just a gram or so below normal, often goes undetected until it shows up on routine bloodwork. You might feel a bit more tired than usual or notice you’re slightly out of breath during exercise, but many people feel nothing at all.
As levels drop further, symptoms become harder to ignore: fatigue, dizziness, pale skin, cold hands and feet, and a rapid or irregular heartbeat. Severe anemia, generally considered hemoglobin below 7 g/dL, can cause visible pallor and significant cardiovascular strain. At that level, hospital patients are typically considered for a blood transfusion, though the decision depends on the individual’s symptoms and overall condition.
The most common cause of anemia worldwide is iron deficiency, but low hemoglobin can also result from chronic kidney disease, vitamin B12 or folate deficiency, blood loss, bone marrow problems, or inherited conditions like sickle cell disease. A single low reading usually prompts follow-up testing to identify the cause before any treatment begins.
What Counts as High Hemoglobin
Hemoglobin above 16.5 g/dL in men or above 16.0 g/dL in women is considered elevated and is sometimes called polycythemia. This means your blood contains more red blood cells than usual, making it thicker and potentially harder to pump. Common symptoms include headaches, blurred vision, itchiness (especially after a warm shower), and a flushed or ruddy complexion.
High hemoglobin can be a response to something in your environment, like living at high altitude or smoking (both of which reduce oxygen delivery, prompting your body to make more red blood cells to compensate). It can also be caused by dehydration, which concentrates your blood and temporarily inflates the reading. Less commonly, it signals a bone marrow disorder called polycythemia vera, where red blood cell production is abnormally ramped up. Your doctor can distinguish between these causes with additional blood tests.
Hemoglobin Levels During Pregnancy
Pregnancy naturally lowers hemoglobin. Your blood volume expands by nearly 50% to support the growing baby, but red blood cell production doesn’t keep pace, so the concentration of hemoglobin drops. This is expected, not alarming, and the diagnostic thresholds for anemia in pregnancy reflect that:
- First trimester: below 11.0 g/dL is considered anemic
- Second trimester: below 10.5 g/dL
- Third trimester: below 11.0 g/dL
The second trimester threshold is slightly lower because that’s when blood volume peaks relative to red blood cell production. Iron-deficiency anemia is especially common during pregnancy because the baby draws heavily on iron stores. Most prenatal care includes hemoglobin checks at the first visit and again around 24 to 28 weeks.
How Altitude and Smoking Shift Your Range
If you live above about 3,000 feet, your body produces extra red blood cells to compensate for the thinner air. That means a hemoglobin of 16 g/dL at 7,000 feet might be perfectly normal, even though it would look borderline high at sea level. Similarly, smoking reduces the oxygen-carrying efficiency of hemoglobin (carbon monoxide from cigarette smoke binds to hemoglobin in place of oxygen), so smokers tend to run higher numbers that don’t actually reflect better oxygen delivery.
Because of this, CDC guidelines recommend adjusting hemoglobin values for both altitude and smoking when screening for anemia. The adjustments are additive, meaning a smoker living in Denver needs a larger correction than either factor alone. Without these adjustments, anemia can be missed in people whose numbers look normal only because altitude or smoking artificially inflated them.
Getting Your Hemoglobin Tested
A hemoglobin test is part of a complete blood count (CBC), one of the most commonly ordered blood tests. It requires a simple blood draw from a vein, usually in your arm. Fasting is not required for a CBC. If your doctor orders a CBC alongside other tests that do require fasting (like a cholesterol panel or fasting glucose), you may be asked to skip food and drinks other than water for 8 to 12 hours beforehand, but that’s for the other tests, not the hemoglobin measurement itself.
Results are usually available within a day. Minor fluctuations between tests are normal. Dehydration can push your reading up by concentrating your blood, while overhydration can dilute it slightly. Vigorous exercise right before a draw can also shift results. For the most consistent reading, stay normally hydrated and avoid intense workouts the morning of your test.