Blood Sugar Units Guide: How to Convert Between mg/dL and mmol/L
Traveling with a glucometer or reading international studies often requires switching between milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L). Here is the exact chemistry and reference table.
Where 18.0182 Comes From
The molecular mass of glucose (C6H12O6) is approximately 180.16 grams per mole. Because 1 liter equals 10 deciliters, 1 mmol/L of glucose equals 18.0182 mg/dL.
To convert mg/dL to mmol/L, divide by 18.0182. To convert mmol/L to mg/dL, multiply by 18.0182.
| Glucose in mg/dL | Glucose in mmol/L | Common Context Note |
|---|---|---|
| 54 mg/dL | 3.0 mmol/L | Level 2 hypoglycemia alert threshold |
| 70 mg/dL | 3.9 mmol/L | Level 1 hypoglycemia alert threshold |
| 90 mg/dL | 5.0 mmol/L | Typical fasting reference example |
| 100 mg/dL | 5.6 mmol/L | Fasting upper normal threshold (ADA) |
| 126 mg/dL | 7.0 mmol/L | Fasting threshold used in clinical testing |
| 140 mg/dL | 7.8 mmol/L | 2-hour post-load reference threshold |
| 180 mg/dL | 10.0 mmol/L | Common upper target bound in CGM consensus |
Limitations and When to Seek Medical Care
- Always verify which unit is printed on your test strip vial and meter screen; misreading mmol/L as mg/dL or vice versa can lead to dangerous dosing errors.
Related Calculators
Blood Glucose Unit Converter (mg/dL ↔ mmol/L)
Convert blood glucose values between milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L) using the exact molar mass factor of glucose (18.0182).
A1C to eAG Calculator
Translate laboratory NGSP HbA1c (%) into estimated average glucose (eAG) in both mg/dL and mmol/L using the Nathan et al. (2008) ADAG linear regression equation.
HbA1c Unit Converter (mmol/mol ↔ %)
Convert laboratory HbA1c results between IFCC standard units (mmol/mol, used in the UK, Europe, and Australia) and NGSP/DCCT percentage units (%, used in the US and Canada) using the published NGSP/IFCC master equation.
Frequently Asked Questions
Can a meter accidentally switch units?
Some meters allow unit changes in setup menus, while others are factory-locked to the country of purchase. Always check the unit label (mg/dL vs mmol/L) next to the number.
Sources and Review Information
- [S9] Nathan DM, Kuenen J, Borg R, et al. Translating the A1C assay into estimated average glucose values (ADAG Study). Diabetes Care. 2008;31(8):1473-1478. Reference Source
Prepared by: GlucoBP Editorial & Engineering Team · Verification status: Formula verified against published reference; clinical review pending · Last updated: 2026-11-15