Blood Sugar Converter

How to Use This Converter

1

Choose your conversion direction

Select mg/dL → mmol/L if you're converting from US units to international units, or mmol/L → mg/dL for the reverse.

2

Enter your blood glucose value

Type the value from your glucose meter, lab report, or CGM. The converter accepts any reading in the normal to high range.

3

Read the converted value

Both units appear instantly — with a clinical context note showing where this reading falls relative to normal fasting and post-meal targets.

The Conversion Formula

Blood glucose unit conversion uses a single factor based on the molecular weight of glucose (180.16 g/mol):

mmol/L = mg/dL ÷ 18.016 mg/dL = mmol/L × 18.016 Factor: 18.016 (molecular weight of glucose ÷ 10)

Quick Reference Conversion Table

mg/dL	mmol/L	Context
70	3.9	Low (hypoglycemia threshold)
80	4.4	Normal fasting (low end)
100	5.6	Normal fasting
126	7.0	High fasting / diabetes threshold
140	7.8	High post-meal (2-hr threshold)
154	8.6	Above ADA target avg (A1C 7%)
180	10.0	High post-meal
200	11.1	Very high / diagnostic threshold
270	15.0	Very high — seek medical advice

Reference ranges vary by individual and test type (fasting vs. post-meal). Source: NIDDK / NIH

Frequently Asked Questions

Why are there two different units for blood sugar?

The United States uses milligrams per deciliter (mg/dL) to measure blood glucose, while most other countries — including the UK, Canada, Australia, and Europe — use millimoles per liter (mmol/L). Both measure the same thing: the concentration of glucose in your blood. The difference is simply the unit of measurement, similar to how temperature is expressed in Fahrenheit or Celsius.

What is a normal blood sugar level in mg/dL and mmol/L?

For fasting blood sugar (no food for 8+ hours), a normal range is 70–99 mg/dL (3.9–5.5 mmol/L). A fasting level of 100–125 mg/dL (5.6–6.9 mmol/L) indicates prediabetes, and 126 mg/dL (7.0 mmol/L) or higher on two occasions indicates diabetes. Post-meal targets (2 hours after eating) are generally below 140 mg/dL (7.8 mmol/L) for most adults.

Is 126 mg/dL the same as 7.0 mmol/L?

Yes. 126 mg/dL ÷ 18.016 = 6.994 mmol/L, which rounds to 7.0 mmol/L. This is clinically significant: a fasting glucose of 126 mg/dL (7.0 mmol/L) or higher on two separate tests is one of the diagnostic criteria for type 2 diabetes, according to ADA and WHO guidelines.

How do I convert 5.6 mmol/L to mg/dL?

Multiply by 18.016: 5.6 × 18.016 = 100.9, which rounds to 101 mg/dL. You can use the converter above to do this instantly for any value.

Can I use blood sugar readings to estimate my A1C?

Yes — if you have an average blood glucose over the past 2–3 months, our Glucose to A1C Calculator can estimate your A1C. This is an approximation based on the ADA ADAG formula and should not replace a lab test.