Free tool · Health & Wellness
Blood sugar converter: mg/dL ↔ mmol/L and A1C
Converts blood glucose readings between the two units used around the world, and estimates average glucose from an A1C (HbA1c) percentage.
General education, not medical advice. Talk to your doctor or pharmacist before changing any treatment. Disclaimer.
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How it works
mg/dL is used mainly in the United States; mmol/L in the UK, Canada, Europe, Australia and most other countries. One mmol/L of glucose equals 18.016 mg/dL, from the molar mass of glucose (180.16 g/mol).
Estimated average glucose (eAG) uses the formula from the A1c-Derived Average Glucose study (Nathan et al., Diabetes Care, 2008): eAG in mg/dL = 28.7 × A1C − 46.7.
mmol/L = mg/dL ÷ 18.016 · mg/dL = mmol/L × 18.016 · eAG (mg/dL) = 28.7 × A1C − 46.7
Worked example
126 mg/dL is 7.0 mmol/L, and 7.0 mmol/L is 126 mg/dL. An A1C of 7% corresponds to an estimated average glucose of about 154 mg/dL (8.6 mmol/L).
Limits
- This is a unit converter, not a diagnosis. It does not tell you whether a reading is normal or what to do about it. Ask your doctor or diabetes team what your targets are.
- Estimated average glucose is a population formula; an individual's average can differ from it.
Questions
Why do some meters show mmol/L and others mg/dL?
Countries standardised on different units. The reading is the same; only the scale differs.
Can I use this to decide on my insulin dose?
No. Never change medicine or insulin based on a converter or website. Follow the plan agreed with your healthcare team.
Sources
- Translating the A1C assay into estimated average glucose values, Diabetes Care (via PubMed), 2008