Question 1

How do you convert mmol/L to mg/dL?

Accepted Answer

It depends on the marker, because the conversion factor is the molecule's molar mass. For blood glucose, multiply mmol/L by 18 to get mg/dL. For cholesterol (total, LDL, HDL), multiply by 38.67. For triglycerides, multiply by 88.57. To go the other way, divide by the same factor.

Question 2

What is a normal blood sugar in mmol/L?

Accepted Answer

A normal fasting blood glucose is below 5.6 mmol/L (100 mg/dL). 5.6–6.9 mmol/L (100–125 mg/dL) is prediabetes, and 7.0 mmol/L (126 mg/dL) or above indicates diabetes. Read against your own lab's range.

Question 3

How do I convert HbA1c between % and mmol/mol?

Accepted Answer

HbA1c uses a different formula: mmol/mol = (percentage − 2.15) × 10.929. So 6.5% is about 48 mmol/mol (the diabetes threshold), and 5.7% is about 39 mmol/mol. % (NGSP) is common in the US; mmol/mol (IFCC) is used in the UK and most of the world.

Question 4

Why do labs use different units?

Accepted Answer

The US typically reports in mg/dL (mass per volume); the UK and most other countries use mmol/L (moles per volume). They measure the same thing — this tool converts between them so a result makes sense wherever it was taken.

Marker	Category	mmol/L	mg/dL
Fasting glucose	Normal	< 5.6	< 100
	Prediabetes	5.6–6.9	100–125
	Diabetes	≥ 7.0	≥ 126
Total cholesterol	Desirable	< 5.2	< 200
	Borderline	5.2–6.2	200–239
	High	≥ 6.2	≥ 240
LDL cholesterol	Optimal	< 2.6	< 100
LDL cholesterol	High	≥ 4.1	≥ 160
HDL cholesterol	Low	< 1.0	< 40
HDL cholesterol	Protective	≥ 1.6	≥ 60
Triglycerides	Normal	< 1.7	< 150
	High	2.3–5.6	200–499
	Very high	≥ 5.6	≥ 500

mmol/L ↔ mg/dL converter

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