Blood Sugar Converter: mg/dL to mmol/L
Convert a blood glucose reading between mg/dL and mmol/L and see where it sits against fasting, after-meal and low blood sugar ranges. All calculations run in your browser and nothing is stored.
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Enter a blood glucose reading to convert it.
Blood sugar ranges
ADA thresholds in both units. Fasting and 2-hour values are diagnostic ranges, confirmed by repeat testing.
| Reading | mg/dL | mmol/L |
|---|---|---|
| Level 2 low | Below 54 | Below 3.0 |
| Level 1 low | 54–69 | 3.0–3.8 |
| Normal fasting | 70–99 | 3.9–5.5 |
| Prediabetes (fasting) | 100–125 | 5.6–6.9 |
| Diabetes range (fasting) | 126 or higher | 7.0 or higher |
| Normal 2 hours after glucose load | Below 140 | Below 7.8 |
| Diabetes range (2 hours) | 200 or higher | 11.1 or higher |
| Common target for people with diabetes | 70–180 | 3.9–10.0 |
mg/dL to mmol/L chart
Common readings converted at 18.016 mg/dL per mmol/L.
| mg/dL | mmol/L |
|---|---|
| 40 | 2.2 |
| 54 | 3.0 |
| 60 | 3.3 |
| 70 | 3.9 |
| 80 | 4.4 |
| 90 | 5.0 |
| 100 | 5.6 |
| 110 | 6.1 |
| 126 | 7.0 |
| 140 | 7.8 |
| 160 | 8.9 |
| 180 | 10.0 |
| 200 | 11.1 |
| 250 | 13.9 |
| 300 | 16.7 |
| 350 | 19.4 |
| 400 | 22.2 |
How it's calculated
mmol/L = mg/dL ÷ 18.016mg/dL = mmol/L × 18.016Sources: ADA Standards of Care 2026: Glycemic Goals and Hypoglycemia; ADA Standards of Care 2026: Diagnosis and Classification; PubChem: D-Glucose (molar mass)
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Frequently asked questions
Why are there two units for blood sugar?
mg/dL measures glucose by weight (milligrams per decilitre) and mmol/L measures it by number of molecules (millimoles per litre). The US and India mostly use mg/dL, while the UK, Canada, Australia and much of Europe use mmol/L. They describe the same reading.
How do I convert mg/dL to mmol/L?
Divide by about 18. The exact factor is 18.016, which comes from the molar mass of glucose (180.16 g/mol). To go the other way, multiply mmol/L by 18.016. For example, 126 mg/dL is 7.0 mmol/L.
What is a normal fasting blood sugar?
Below 100 mg/dL (5.6 mmol/L) is normal after at least eight hours without food. 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is the prediabetes range, and 126 mg/dL (7.0 mmol/L) or higher on repeat testing is in the diabetes range.
What counts as low blood sugar?
The ADA defines level 1 hypoglycaemia as below 70 mg/dL (3.9 mmol/L) and level 2 as below 54 mg/dL (3.0 mmol/L). Level 2 needs prompt action. Anyone who uses insulin or sulfonylureas should follow the plan agreed with their care team.
What should blood sugar be after eating?
In a glucose tolerance test, a level below 140 mg/dL (7.8 mmol/L) two hours after the glucose drink is normal, 140 to 199 mg/dL is the prediabetes range and 200 mg/dL (11.1 mmol/L) or higher is the diabetes range. Everyday meals vary, so treat this as a guide.
What target range do people with diabetes use?
A common target for time in range is 70 to 180 mg/dL (3.9 to 10.0 mmol/L), the range FitDose charts readings against. Individual targets can differ, so use the one your care team has set for you.
How does this relate to A1c?
A single reading is a moment in time, while A1c reflects your average over about three months. Use the A1c calculator to turn an A1c result into an estimated average glucose in either unit.
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