Select Analyte
Select an analyte above to begin converting
Complete Reference Table — All Analytes
| Analyte | Conversion Factor | Normal (mg/dL) | Normal (mmol/L) | Notes |
|---|
Why Units Differ Between Countries
The United States, most of South Asia (including India), and parts of Asia use conventional units — primarily mg/dL (milligrams per decilitre). Most of Europe, Australia, Canada, and other countries use SI units — primarily mmol/L (millimoles per litre). This creates confusion when interpreting imported diagnostic guidelines, clinical trial endpoints, and drug thresholds. For example, a fasting glucose of 126 mg/dL (US diabetes threshold) equals 7.0 mmol/L (UK/ADA equivalent). A cholesterol of 200 mg/dL (borderline high in US guidelines) equals 5.17 mmol/L (UK threshold for statin consideration is 5.0 mmol/L). Understanding both unit systems is essential for any clinician working with international guidelines.
Key Clinical Conversion Benchmarks to Memorise
These are the most clinically important conversion pairs that every physician should know from memory:
- Glucose: 18 mg/dL = 1 mmol/L. Fasting normal: 70–100 mg/dL = 3.9–5.6 mmol/L. Diabetes threshold: 126 mg/dL = 7.0 mmol/L. Hypoglycaemia: <70 mg/dL = <3.9 mmol/L
- Creatinine: 1 mg/dL ≈ 88.4 µmol/L. Normal male: 0.7–1.2 mg/dL = 62–106 µmol/L. AKI Stage 1: ≥1.5× baseline
- Cholesterol: Divide mg/dL by 38.67 for mmol/L. Total cholesterol 200 mg/dL = 5.17 mmol/L. LDL target ≤70 mg/dL = 1.81 mmol/L
- Triglycerides: Divide mg/dL by 88.57 for mmol/L. High: ≥150 mg/dL = 1.7 mmol/L. Very high: ≥500 mg/dL = 5.65 mmol/L (pancreatitis risk)
- Bilirubin: Divide mg/dL by 17.1 for µmol/L. Jaundice threshold: ~3 mg/dL = 51 µmol/L (clinically visible scleral icterus typically at >2.5–3 mg/dL)
- Uric acid: Divide mg/dL by 59.48 for mmol/L. Gout treatment target: <6 mg/dL = <357 µmol/L (some guidelines <5 mg/dL = <297 µmol/L for tophaceous gout)
Frequently Asked Questions
Why are different units used for the same lab test?
Laboratory units vary by country and historical convention. The SI system (Système International) uses molar units (mmol/L, µmol/L) preferred in Europe, Australia, and Canada. Conventional units (mg/dL, g/dL, mEq/L) are used in the USA, India, and much of Asia. Both systems are valid — the conversion factor depends on the molecular weight of the substance being measured.
How do I convert mg/dL to mmol/L?
mmol/L = mg/dL ÷ (molecular weight / 10). For glucose: MW = 180, so 1 mmol/L = 18 mg/dL (glucose 126 mg/dL = 7.0 mmol/L). For creatinine: MW = 113, so 1 mg/dL = 88.4 µmol/L. For urea: MW = 60, so 1 mg/dL urea = 0.357 mmol/L (but BUN uses nitrogen MW = 28, so 1 mg/dL BUN = 0.714 mmol/L urea).
What is the difference between BUN and serum urea?
BUN (Blood Urea Nitrogen) measures only the nitrogen component of urea (MW 28), while serum urea measures the whole urea molecule (MW 60). BUN is used in the USA and India (mg/dL). Serum urea in mmol/L is used in UK/Europe. Conversion: Urea (mmol/L) = BUN (mg/dL) × 0.357; or BUN (mg/dL) = Urea (mmol/L) × 2.8. Normal BUN: 7–20 mg/dL; Normal serum urea: 2.5–7.1 mmol/L.
How is HbA1c converted between % and mmol/mol?
DCCT % to IFCC mmol/mol: mmol/mol = (HbA1c% − 2.15) × 10.929. Example: HbA1c 7% = (7 − 2.15) × 10.929 = 53 mmol/mol. Reverse: HbA1c% = (mmol/mol ÷ 10.929) + 2.15. India uses DCCT % (ADA/RSSDI guidelines). UK/Europe use IFCC mmol/mol. Most modern lab analysers report both.
What are common unit conversion errors in clinical practice?
Dangerous errors: confusing mg/dL and mmol/L for glucose (factor of 18 — misreading 18 mmol/L as 18 mg/dL would be life-threatening); confusing BUN and urea values (factor of 2.8); confusing µg/mL and µg/dL for drug levels (factor of 100); and confusing ng/mL and ng/dL for hormones (factor of 100). Always check units when receiving results from a different laboratory system.
How do I convert cholesterol and lipid units?
Total cholesterol, LDL, HDL: mg/dL × 0.0259 = mmol/L. Example: LDL 130 mg/dL = 3.37 mmol/L. Triglycerides: mg/dL × 0.0113 = mmol/L. Example: TG 150 mg/dL = 1.70 mmol/L. Indian labs report in mg/dL. UK/Europe use mmol/L. ATP III/AHA targets are in mg/dL; ESC/EAS targets are in mmol/L — always check which system the guideline uses.
Related Calculators
⚠ Medical Disclaimer: Normal ranges shown are general reference ranges from major laboratory textbooks. Reference ranges vary by laboratory, analyser, patient age, sex, and pregnancy status. Always interpret results against the reference range provided by your specific laboratory report. This tool is for reference and educational purposes only.