Hemoglobin Unit Converter (g/dL ↔ mmol/L)

The hemoglobin conversion factor and where it comes from

Hemoglobin is the oxygen-carrying protein in red blood cells, measured as part of a complete blood count (CBC). Hemoglobin is reported in g/dL on U.S. reports, in g/L on many European reports (g/L = 10 × g/dL), and occasionally in mmol/L in the Netherlands and parts of Scandinavia.

The standard conversion factor for hemoglobin is 0.6206, applied as g/dL × 0.6206 = mmol/L (and mmol/L ÷ 0.6206 = g/dL in reverse). Hemoglobin's mmol/L value is referenced to the heme-bearing monomer (molecular weight 16,114 g/mol), giving 1 g/dL = 0.6206 mmol/L. Because most searches ask about g/L (used in many European CBC reports), note that g/L = 10 × g/dL, so 1 g/L = 0.06206 mmol/L. Source: IFCC / standard hemoglobin SI convention (monomer molecular weight 16,114 g/mol).

Published reference intervals

The intervals below are reproduced from U.S. National Library of Medicine, MedlinePlus: Hemoglobin test. They are listed here for unit reference only. Whether any value is in range for you depends on your laboratory's own reference range and your clinical context, so read them alongside your report and your healthcare provider, not in place of either.

Reference ranges vary by laboratory, altitude, age, and sex; the values above are representative adult ranges published by the source.

Pre-computed hemoglobin conversions

Dedicated answer pages for the hemoglobin values people search for most. Each shows the answer, the math, and a table of nearby values.

g/dL to mmol/L

• 42 g/L to mmol/L

Common questions

How do I convert hemoglobin from g/dL to mmol/L?

Multiply by 0.6206: g/dL × 0.6206 = mmol/L. To go the other way, divide by 0.6206 (or multiply by 1.611).

What is the hemoglobin conversion factor?

0.6206. Hemoglobin's mmol/L value is referenced to the heme-bearing monomer (molecular weight 16,114 g/mol), giving 1 g/dL = 0.6206 mmol/L. Because most searches ask about g/L (used in many European CBC reports), note that g/L = 10 × g/dL, so 1 g/L = 0.06206 mmol/L.

Where is g/dL used and where is mmol/L used?

Hemoglobin is reported in g/dL on U.S. reports, in g/L on many European reports (g/L = 10 × g/dL), and occasionally in mmol/L in the Netherlands and parts of Scandinavia.

Related converters and reference

• Full blood test unit converter: 60+ biomarkers, any value, either direction.
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