Blood Sugar Converter
US lab reports and glucose meters read in mg/dL; most of the rest of the world uses mmol/L. If you're reading an international study, using a meter from another country, or comparing reports across systems, this converter flips glucose values instantly in both directions — and the chart below covers the common fasting, post-meal, and A1c-related ranges at a glance.
Enter the number exactly as shown on your report or meter
US reports and meters are usually mg/dL; UK/Canada/Europe/Australia are usually mmol/L
Enter your values above to see your results.
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How it works
The conversion factor
mmol/L = mg/dL ÷ 18.016 (usually rounded to ÷18), and mg/dL = mmol/L × 18.016. The factor comes from glucose's molecular weight (180.16 g/mol) — the same logic as cholesterol unit conversion, just a different molecule. Example: 100 mg/dL ≈ 5.6 mmol/L; 7.0 mmol/L ≈ 126 mg/dL.
Which unit does my report use?
US labs and US-sold glucose meters report mg/dL. The UK, Canada, Australia, and most of Europe report mmol/L. The unit is printed next to the value on lab reports, and meters usually show it on screen or in settings — check before converting.
Conversion vs A1c estimation
This page converts between two units that measure the same thing — glucose concentration right now. Converting blood sugar to an estimated A1c is a different operation (A1c reflects a ~3-month average, not a unit change). For that, use our A1c ↔ Average Glucose Converter.
Blood sugar conversion chart: common values at a glance
Everyday reference points in both units — fasting range, post-meal, and the thresholds used in standard diabetes-screening criteria.
| Context | mg/dL | mmol/L |
|---|---|---|
| Low blood sugar (hypoglycemia alert) | <70 | <3.9 |
| Normal fasting, lower bound | 70 | 3.9 |
| Normal fasting, upper bound | 99 | 5.5 |
| Impaired fasting glucose range | 100–125 | 5.6–6.9 |
| Diabetes screening threshold (fasting) | ≥126 | ≥7.0 |
| Normal 2h after meal (OGTT), upper bound | 140 | 7.8 |
| Diabetes screening threshold (2h OGTT) | ≥200 | ≥11.1 |
| Typical target peak after meals | <180 | <10.0 |
Thresholds shown are the standard ADA/WHO screening criteria for orientation. Whether a value matters depends on context — a single reading is a screening signal, not a diagnosis.
Frequently asked questions
How do I convert blood sugar from mg/dL to mmol/L?
Divide by 18 (more precisely, 18.016). Example: 126 mg/dL ÷ 18.016 ≈ 7.0 mmol/L. The converter above does it instantly, and the chart covers the common reference points.
How do I convert mmol/L to mg/dL?
Multiply by 18 (more precisely, 18.016). Example: 5.5 mmol/L × 18.016 ≈ 99 mg/dL.
Why are there two units for blood sugar?
mg/dL measures the mass of glucose per volume of blood; mmol/L counts molecules per volume. The US uses mg/dL, while the UK, Canada, Australia, and most of Europe standardized on mmol/L (SI units). They describe the same concentration on different scales — 100 mg/dL and 5.6 mmol/L are the same blood sugar.
What is a normal fasting blood sugar in mmol/L?
The usual normal fasting range is 70–99 mg/dL, which is 3.9–5.5 mmol/L. Impaired fasting glucose is 100–125 mg/dL (5.6–6.9 mmol/L), and the standard fasting screening threshold for diabetes is 126 mg/dL (7.0 mmol/L). Any threshold-crossing value should be confirmed by a clinician — screening criteria, not a diagnosis.
Is converting blood sugar the same as converting to A1c?
No. mg/dL ↔ mmol/L is a unit conversion of the same instant measurement. A1c is a separate marker reflecting average glucose over roughly three months — translating between glucose and A1c uses an estimated-average-glucose formula, not a unit factor. See our A1c ↔ Average Glucose Converter for that.
Do I use the same factor for cholesterol?
No — each analyte has its own factor based on molecular weight. Glucose is ÷18; cholesterol is ÷38.67; triglycerides are ÷88.57. For cholesterol and triglyceride conversions, use our Cholesterol Units Converter.
Sources
- NCBI Bookshelf: SI unit conversion tables for clinical chemistry — glucose mg/dL ↔ mmol/L (factor 18.016).
- ADA Standards of Care in Diabetes — fasting and OGTT screening thresholds (70/100/126/200 mg/dL reference points).
This calculator is for informational purposes only and is not medical advice, diagnosis, or treatment. Reference ranges are general population guidelines — always discuss your lab results with a qualified healthcare professional.