About the Blood Sugar Converter
This blood sugar converter translates glucose readings between the two units used worldwide: milligrams per decilitre (mg/dL), used in the US, and millimoles per litre (mmol/L), used in the UK, Canada, Australia and most of Europe. Enter a reading in either unit and you get the other instantly, plus an interpretation based on when the reading was taken.
It is handy when your meter, a lab report or an online article uses a different unit from the one you know, when you travel with a glucose meter, or when you compare CGM data with guidelines. Choose fasting, two hours after a meal (or glucose tolerance test) or random, and the tool applies the matching American Diabetes Association thresholds.
The calculator also shows the HbA1c that would correspond to this value if it were your average glucose over about three months. A single reading cannot diagnose diabetes — diagnosis needs lab tests, usually repeated.
With the default inputs, the converted value is 5.3. Change any value above to recalculate instantly.
How to use the blood sugar converter
- 1Enter your glucose reading.
- 2Choose which unit the reading is in.
- 3Select whether it was fasting, two hours after a meal, or random.
- 4Read the converted value and what the range means.
Formula and method
Glucose has a molar mass of 180.16 g/mol. One mmol/L therefore equals 180.16 mg per litre, or 18.016 mg per decilitre, so converting is a single multiplication or division (many charts round the factor to 18).
Interpretation follows American Diabetes Association thresholds: fasting glucose under 100 mg/dL (5.6 mmol/L) is normal, 100–125 is prediabetes and 126 or more suggests diabetes; a 2-hour OGTT value under 140 is normal, 140–199 prediabetes and 200+ diabetes. Below 70 mg/dL is hypoglycemia. The equivalent HbA1c uses the ADAG relation eAG = 28.7 × A1c − 46.7.
- 18.016
- mg/dL per mmol/L for glucose
- eAG
- Estimated average glucose in mg/dL
Worked examples
Fasting 95 mg/dL to mmol/L
95 ÷ 18.016 = 5.27 mmol/L. A fasting value below 100 mg/dL (5.6 mmol/L) is in the normal range.
7.8 mmol/L two hours after eating
7.8 × 18.016 = 140.5 mg/dL. A two-hour value between 140 and 199 mg/dL falls in the impaired glucose tolerance (prediabetes) range.
Fasting 130 mg/dL
130 mg/dL is 7.2 mmol/L. Fasting values of 126 mg/dL or more on two occasions meet the diagnostic threshold for diabetes. If 130 were your average glucose, it would correspond to an HbA1c of about 6.2%.
Frequently asked questions
How do I convert mg/dL to mmol/L?+
Divide the mg/dL value by 18 (more precisely 18.016). For example, 100 mg/dL ÷ 18 = 5.6 mmol/L. To go the other way, multiply mmol/L by 18.
What is a normal blood sugar level?+
For adults without diabetes, fasting glucose is normally 70–99 mg/dL (3.9–5.5 mmol/L) and under 140 mg/dL (7.8 mmol/L) two hours after eating.
What blood sugar level is dangerous?+
Below 70 mg/dL (3.9 mmol/L) is hypoglycemia and below 54 mg/dL (3.0 mmol/L) is clinically significant. Very high levels, especially above 250–300 mg/dL with ketones or symptoms, need prompt medical advice.
Why do countries use different glucose units?+
The US and a few other countries report mass concentration (mg/dL), while most others adopted SI molar units (mmol/L). The chemistry is identical; only the unit differs.
What are target glucose levels for people with diabetes?+
The ADA suggests 80–130 mg/dL (4.4–7.2 mmol/L) before meals and under 180 mg/dL (10 mmol/L) one to two hours after meals for many adults, but individual targets should be set with your care team.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.