How do you convert blood alcohol (ethanol) from mg/dL to mmol/L?

Divide by the molar mass. For blood alcohol (ethanol) (46.068 g/mol), 1 mg/dL = 0.21707 mmol/L.

Why isn't there one factor for mg/dL to mmol/L?

Because mg measures mass and mmol measures amount of substance, the factor depends on the molar mass of what is being measured. Every analyte has its own.

Calculators › Blood alcohol (ethanol)

Blood alcohol (ethanol): mg/dL to mmol/L

1 mg/dL = 0.21707 mmol/L

Reference only. These conversions are arithmetic, not medical advice. Reference ranges differ between laboratories, and results should be interpreted by a clinician alongside the lab's own reported units and ranges.

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Conversion table

mg/dL	mmol/L
20 mg/dL	4.3414 mmol/L
50 mg/dL	10.8535 mmol/L
80 mg/dL	17.3656 mmol/L
100 mg/dL	21.707 mmol/L
150 mg/dL	32.5606 mmol/L
200 mg/dL	43.4141 mmol/L
300 mg/dL	65.1211 mmol/L

Going the other way, 1 mmol/L = 4.6068 mg/dL.

Why this conversion needs the substance

mg/dL measures mass; mmol/L measures amount of substance. Converting between them needs the molar mass of the thing being measured — for blood alcohol (ethanol) that is 46.068 g/mol. That is why a generic converter can't do it, and why every analyte has a different factor.

Jotal works this out from molar mass rather than a stored factor, so write ethanol 100 mg/dL in mmol/L and it answers 21.707 mmol/L. Leave the substance out and it deliberately returns nothing rather than guessing.

Other lab values

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