Article — mmol/L to mg/dL Converter
mmol/L to mg/dL converter: lab unit conversion for blood markers
mmol/L to mg/dL conversion depends on the analyte’s molecular weight. Glucose multiplies by 18.0156. Cholesterol multiplies by 38.67. Triglycerides multiply by 88.57. Creatinine multiplies by 11.31. BUN multiplies by 2.80. A fasting glucose of 5.6 mmol/L equals 100 mg/dL — the upper end of normal. A 7.0 mmol/L glucose equals 126 mg/dL — the diabetes diagnostic threshold.
This converter is an educational tool. Lab values must be interpreted by a healthcare professional in the context of clinical history, other tests, the laboratory’s reference ranges and the individual patient. Do not use this calculator to self-diagnose or adjust medications.
What mmol/L and mg/dL mean
Both units measure how much of a substance is present in a volume of blood, but they count it differently. mmol/L counts molecules. mg/dL weighs them.
A millimole (mmol) is one-thousandth of a mole, and a mole is Avogadro’s number of molecules — 6.022 × 10²³ of them. mmol/L tells you how many millimoles of the analyte sit in one litre of blood. A milligram (mg) is one-thousandth of a gram; mg/dL tells you how many milligrams sit in one decilitre (100 mL) of blood. Same chemistry, different framing.
The mole was added to the International System of Units (SI) in 1971. Before that, clinical labs worldwide used mg/dL by convention. After 1971 most countries shifted their lab reports to mmol/L because the molar unit is more meaningful chemically — it directly reflects the number of molecules participating in biochemical reactions. The United States is the main exception; mg/dL remains standard in US clinical reporting, though research papers usually publish in mmol/L for international consistency.
The mmol/L to mg/dL formula
The general mmol/L to mg/dL conversion formula uses the molecular weight (MW) of the analyte.
mg/dL = mmol/L × MW / 10mmol/L = mg/dL × 10 / MWMW in g/mol (grams per mole)The division by 10 reconciles the volume units: a decilitre is 100 mL, a litre is 1000 mL, so dL is 1/10 of L. Multiply by molecular weight to convert counts to mass; divide by 10 to convert per-litre to per-decilitre.
Every analyte has its own molecular weight and its own conversion factor. Glucose (MW 180) gives a factor of 18. Cholesterol (MW 386.65) gives 38.67. Triglycerides (MW 885.7) give 88.57. The factor is a fixed physical constant — there is no measurement uncertainty in it, only in the lab value being converted.
Glucose conversion mmol/L to mg/dL
Glucose is the most commonly converted analyte. The mental shortcut is ×18.
- 3.0 mmol/L = 54 mg/dL (severe hypoglycemia)
- 4.0 mmol/L = 72 mg/dL (normal fasting low)
- 5.0 mmol/L = 90 mg/dL (normal fasting)
- 5.6 mmol/L = 100 mg/dL (upper normal / prediabetes threshold)
- 7.0 mmol/L = 126 mg/dL (diabetes diagnostic, fasting)
- 10.0 mmol/L = 180 mg/dL (hyperglycemia)
- 11.1 mmol/L = 200 mg/dL (diabetes diagnostic, random or 2-h OGTT)
- 13.9 mmol/L = 250 mg/dL (very elevated)
The ADA Standards of Care 2026 use the same numerical thresholds in both unit systems, just expressed differently. Fasting plasma glucose under 100 mg/dL (5.6 mmol/L) is normal. 100-125 mg/dL (5.6-6.9 mmol/L) is impaired fasting glucose, the prediabetes range. 126 mg/dL (7.0 mmol/L) or higher on two separate occasions is diagnostic of diabetes.
Cholesterol and triglyceride conversion
Cholesterol uses a factor of 38.67. The same factor applies to total cholesterol, LDL and HDL because all three measure the same cholesterol molecule, just carried in different lipoprotein particles.
Triglycerides need a different factor — 88.57 — because the triglyceride molecule is heavier than cholesterol. The NIH National Cholesterol Education Program uses triolein (MW 885.7 g/mol) as the reference triglyceride. Borderline-high triglycerides start at 1.7 mmol/L (150 mg/dL); high is 2.3 mmol/L (200 mg/dL); very high is 5.65 mmol/L (500 mg/dL), where pancreatitis risk rises sharply.
Renal markers: creatinine and BUN
Creatinine and urea/BUN are the standard renal function markers. Both have their own conversion factors.
Creatinine has molecular weight 113.12 g/mol, giving a factor of 11.31. A serum creatinine of 88 µmol/L (the common unit at this low concentration) is 1.0 mg/dL — within the normal adult range. Reference ranges in mg/dL: adult men 0.7-1.3, adult women 0.6-1.1. Higher values indicate reduced glomerular filtration.
BUN — blood urea nitrogen — is the US-specific report. It measures only the nitrogen content of the urea molecule, not the whole urea. So the BUN factor is 2.801 (the MW of nitrogen, 28.01, divided by 10). Outside the US, labs report whole urea with factor 6.006. The two reports differ by a factor of 2.14. To compare a US BUN with a non-US urea value, multiply BUN by 2.14 — or use the calculator above and pick the right analyte.
Country reporting conventions
Knowing which unit system your lab uses prevents misreading by a factor of 10-90 depending on the analyte.
- United States = mg/dL for glucose, cholesterol, triglycerides; BUN for urea
- United Kingdom = mmol/L for all; whole urea
- Canada = mmol/L for all; whole urea
- Australia / New Zealand = mmol/L for all
- European Union (most) = mmol/L for all; some German labs report mg/dL for glucose historically
- Russia and post-Soviet states = mmol/L
- India = mg/dL for glucose (US convention), mmol/L for some other labs
If a patient travels between unit systems — common for international students, expatriates, and people who manage their own diabetes — converting reports is routine. Hospital labs include the conversion factor on their reference sheets, but most patients do not see those documents.
Diabetes reference ranges in both units
The ADA and WHO use the same numerical thresholds; only the unit changes.
Fasting plasma glucose: normal < 5.6 mmol/L (< 100 mg/dL); prediabetes (impaired fasting glucose) 5.6-6.9 mmol/L (100-125 mg/dL); diabetes ≥ 7.0 mmol/L (≥ 126 mg/dL).
2-hour oral glucose tolerance test: normal < 7.8 mmol/L (< 140 mg/dL); impaired glucose tolerance 7.8-11.0 mmol/L (140-199 mg/dL); diabetes ≥ 11.1 mmol/L (≥ 200 mg/dL).
Random glucose with symptoms: diabetes ≥ 11.1 mmol/L (≥ 200 mg/dL).
HbA1c: normal < 5.7%; prediabetes 5.7-6.4%; diabetes ≥ 6.5%. A1c uses % or mmol/mol units rather than mmol/L, since it measures glycated hemoglobin proportions, not blood glucose concentration directly.
Common mmol/L conversion mistakes
Three errors account for almost all unit-conversion mistakes in clinical reports.
Using the glucose factor on cholesterol. A patient reads a UK cholesterol report of 5.5 mmol/L, multiplies by 18, and gets 99 mg/dL — which would be impossibly low. The correct factor is 38.67, giving 213 mg/dL — borderline high. Different analyte, different MW, different factor.
Confusing BUN and urea. A 7 mmol/L urea (UK) is not the same as a 7 mg/dL BUN (US). 7 mmol/L urea = 42 mg/dL urea = 19.6 mg/dL BUN. The 2.14 ratio between US BUN and non-US urea catches people often.
Decimal-point errors. A 5.6 mmol/L glucose is 100 mg/dL, not 1000 or 10. If a converted value seems an order of magnitude off, it usually is — recheck the placement of the decimal in the input.