Typical hemoglobin levels vary depending on several factors. Having high or low levels can indicate certain medical conditions, such as diseases affecting the heart and kidneys.

Hemoglobin is a protein in red blood cells that carries iron. It’s responsible for holding oxygen and moving it to the rest of your body.

When your blood doesn’t contain enough hemoglobin, your cells don’t receive enough oxygen. This is known as anemia, which affects up to 1 in 3 people globally.

Doctors determine your hemoglobin level by analyzing a blood sample.

Keep reading to learn more about what’s considered a normal, high, and low hemoglobin level.

Hemoglobin levels are measured in grams per deciliter (g/dL) of blood.

Several factors may affect your hemoglobin levels, such as age, sex assigned at birth, and medical history.

It’s also important to note that healthy ranges may vary slightly from one laboratory to another.

Adults

In adults, the average hemoglobin level is slightly higher for males than females.

SexNormal hemoglobin level (g/dL)
Female12 to 15
Male13.5 to 18

Older adults tend to have lower hemoglobin levels. This may be due to several factors, including:

Children

Infants have higher hemoglobin levels than adults because they have higher oxygen levels in the womb and need more red blood cells to transport the oxygen. This level starts to go down after several weeks.

Below are the hemoglobin ranges from the United Kingdom’s National Health Service in North Bristol:

AgeHemoglobin levels (g/dL)
0 to 14 days14 to 24
15 to 30 days13.4 to 19.8
31 to 60 days13.4 to 19.8
2 to 6 months9.4 to 13
6 to 12 months11.1 to 14.1
1 to 6 years11.5 to 14
6 to 12 years11.5 to 15.5
12 to 18 years? Females: 12 to 16
? Males: 13 to 17

High hemoglobin levels generally accompany high red blood cell counts, known as polycythemia.

A high red blood cell count and hemoglobin level may indicate several things, including:

Symptoms

Many people don’t experience symptoms of high hemoglobin levels. However, in some cases, you may experience:

Risk factors

You may be more likely to have high hemoglobin levels if you:

  • have a family history of disorders that affect red blood cell counts, such as altered oxygen sensing
  • live at a high altitude
  • smoke

A low hemoglobin level is usually seen with low red blood cell counts, known as anemia.

The biggest risk factors for low hemoglobin levels are big amounts of blood loss. Common causes include:

Low hemoglobin may also be genetic or caused by some medical conditions, including:

Symptoms

Like high hemoglobin, not everyone experiences symptoms of low hemoglobin. However, some possible symptoms include:

Risk factors

You may also be more likely to have low hemoglobin levels if you:

When having blood work done, you might also see results for hemoglobin A1c (HbA1c), sometimes called glycated hemoglobin. An HbA1c test measures the amount of glycated hemoglobin, which is hemoglobin that has glucose attached to it.

Doctors often order this test for people with diabetes to get a better idea of their average glucose levels over the course of 2 to 3 months.

Glucose, or blood sugar, circulates throughout your blood and attaches to hemoglobin. The more glucose in your blood, the more likely you will have higher glycated hemoglobin levels.

Glucose stays attached to hemoglobin for about 120 days, so a high HbA1c level indicates your blood sugar has been high for several months.

If you have diabetes, it’s best to aim for an HbA1c level of less than 6.5%. Those without diabetes tend to have HbA1c levels below 5.7%.

If you have diabetes and a high HbA1c level, you may need to adjust your treatment plan.

It’s important to note that hemoglobin HbA1c is not used to measure total hemoglobin levels and doesn’t diagnose anemia or polycythemia.

Learn more about controlling HbA1c levels.

What is considered a bad hemoglobin level?

Low hemoglobin levels are below 12 g/dL for adult females and 13.5 for adult males. High hemoglobin levels are above 15 g/dL for adult females and 18 g/dL for adult males.

What is a 7.0 hemoglobin level?

A hemoglobin test result of 7 g/dL will indicate low hemoglobin levels, which may be a sign of anemia. A doctor can help determine the underlying cause and develop a treatment plan.

What does it mean if your hemoglobin is low?

Low hemoglobin may indicate anemia, heavy bleeding, pregnancy, or chronic health conditions that affect your bones, kidneys, or red blood cells. A doctor could provide a proper diagnosis and treatment plan.

What is the normal hemoglobin level for a female?

A normal hemoglobin level for adult females is 12 to 15 g/dL.

Hemoglobin levels may vary by age, medical condition, and sex assigned at birth.

A high or low hemoglobin level may indicate various things, but some people naturally have higher or lower levels.

A doctor will look at your results in the context of your overall health to determine whether your levels indicate an underlying condition.