Guide
Blood sugar conversion: mg/dL to mmol/L
Glucose meters and lab reports use either mg/dL or mmol/L, and some countries use g/L. Here is how to convert between them, a chart of common values and the reference ranges for fasting and after-meal readings.
How to convert mg/dL to mmol/L
Glucose has a molar mass of 180.16 g/mol, so 1 mmol/L equals 18.016 mg/dL. To convert mg/dL to mmol/L, divide by 18 (precisely 18.016). To convert mmol/L to mg/dL, multiply by 18.
mmol/L = mg/dL ÷ 18.016 · mg/dL = mmol/L × 18.016
For example, 100 mg/dL ÷ 18.016 ≈ 5.6 mmol/L, and 7.0 mmol/L × 18.016 ≈ 126 mg/dL.
The US, India, Japan, Germany, Italy and many other countries mostly use mg/dL. The UK, Canada, Australia and much of Northern Europe use mmol/L. Most meters can be switched between the two in their settings.
mg/dL to mmol/L conversion chart
| mg/dL | mmol/L | g/L |
|---|---|---|
| 40 | 2.2 | 0.40 |
| 54 | 3.0 | 0.54 |
| 60 | 3.3 | 0.60 |
| 70 | 3.9 | 0.70 |
| 80 | 4.4 | 0.80 |
| 90 | 5.0 | 0.90 |
| 100 | 5.6 | 1.00 |
| 110 | 6.1 | 1.10 |
| 120 | 6.7 | 1.20 |
| 126 | 7.0 | 1.26 |
| 130 | 7.2 | 1.30 |
| 140 | 7.8 | 1.40 |
| 150 | 8.3 | 1.50 |
| 160 | 8.9 | 1.60 |
| 180 | 10.0 | 1.80 |
| 200 | 11.1 | 2.00 |
| 220 | 12.2 | 2.20 |
| 250 | 13.9 | 2.50 |
| 280 | 15.5 | 2.80 |
| 300 | 16.7 | 3.00 |
| 350 | 19.4 | 3.50 |
| 400 | 22.2 | 4.00 |
mmol/L to mg/dL conversion chart
| mmol/L | mg/dL |
|---|---|
| 3.0 | 54 |
| 3.9 | 70 |
| 4.0 | 72 |
| 4.4 | 79 |
| 5.0 | 90 |
| 5.5 | 99 |
| 6.0 | 108 |
| 6.5 | 117 |
| 7.0 | 126 |
| 8.0 | 144 |
| 9.0 | 162 |
| 10.0 | 180 |
| 11.1 | 200 |
| 12.0 | 216 |
| 13.9 | 250 |
| 15.0 | 270 |
| 20.0 | 360 |
| 25.0 | 450 |
| 30.0 | 540 |
Blood sugar in g/L
Lab reports in France and some other countries give glucose in grams per litre. Multiply by 100 to get mg/dL, or by 5.55 to get mmol/L: 1.10 g/L is 110 mg/dL (6.1 mmol/L), and 1.26 g/L is 126 mg/dL (7.0 mmol/L).
Reference ranges for blood sugar
- Fasting, without diabetes: 70–99 mg/dL (3.9–5.5 mmol/L)
- Fasting, prediabetes: 100–125 mg/dL (5.6–6.9 mmol/L)
- Fasting, diabetes range: 126 mg/dL (7.0 mmol/L) or higher on two occasions
- Two hours after a glucose drink (OGTT): below 140 mg/dL (7.8 mmol/L) is normal
- Low blood sugar (hypoglycemia): below 70 mg/dL (3.9 mmol/L)
For people with diabetes, the ADA suggests as a general starting point 80–130 mg/dL (4.4–7.2 mmol/L) before meals and below 180 mg/dL (10.0 mmol/L) one to two hours after the start of a meal. Your own targets may differ.
Tips when you switch units
If you move country, change meters or read a lab report from abroad, check the unit before comparing numbers: a fasting value of 5.5 looks alarming only until you notice it is mmol/L (99 mg/dL). Values below about 35 are almost always mmol/L; values above about 40 are almost always mg/dL.
Plasma and whole-blood values also differ slightly. Modern meters are calibrated to report plasma-equivalent values, matching the lab.
The factor 18 applies only to glucose. Cholesterol uses about 38.67 and triglycerides about 88.57.
From single readings to A1C
A single reading tells you how your glucose is right now. A1C reflects the average of roughly the past three months. The ADAG formula links the two: an A1C of 7% corresponds to an estimated average glucose of about 154 mg/dL (8.6 mmol/L).
This page is for information only and is not medical advice.
Sources
- American Diabetes Association. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2025. Diabetes Care 2025;48(Suppl 1):S27–S49.
- American Diabetes Association. Glycemic Goals and Hypoglycemia: Standards of Care in Diabetes—2025. Diabetes Care 2025;48(Suppl 1).
- Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31(8):1473–1478.