Blood sugar converter

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

Convert blood glucose between mmol/L and mg/dL, and HbA1c between mmol/mol and %, with the estimated average glucose.

Your reading

Convert

Glucose

mmol/L

Unit

In the other unit

99 mg/dL

5.5 mmol/L is 99 mg/dL.

IUPAC abridged standard atomic weights

Glucose in both units

Common glucose values in mmol/L and mg/dL.

Glucose in both units
mmol/L	mg/dL
3.0 mmol/L	54 mg/dL
4.0 mmol/L	72 mg/dL
5.0 mmol/L	90 mg/dL
6.0 mmol/L	108 mg/dL
7.0 mmol/L	126 mg/dL
8.0 mmol/L	144 mg/dL
9.0 mmol/L	162 mg/dL
10.0 mmol/L	180 mg/dL
12.0 mmol/L	216 mg/dL
15.0 mmol/L	270 mg/dL
20.0 mmol/L	360 mg/dL

Good to know

Labs and meters round their results, so a converted value can differ from a printed one by the last digit.
The estimated average glucose comes from a study of 507 adults. Your own average can differ, for example with anaemia or some haemoglobin variants, and it says nothing about highs and lows.
This converts units only. Ask your doctor or diabetes nurse what your results mean and before changing any treatment.

Convert blood glucose between mmol/L and mg/dL, and HbA1c between mmol/mol and %, with the estimated average glucose.

How to use

Choose glucose for a meter or lab reading, or HbA1c for a long-term result.
Enter the value and choose the unit it is in.
Read it in the other unit; for HbA1c also the estimated average glucose.

How it works

Blood glucose is measured in two units around the world. Millimoles per litre (mmol/L) count glucose molecules; milligrams per decilitre (mg/dL) weigh them. HbA1c, the share of haemoglobin with sugar attached, shows your average over two to three months and is also reported two ways: in mmol/mol (the international IFCC unit) or in % (the older NGSP/DCCT unit).

One mole of glucose (C₆H₁₂O₆) weighs 180.156 g, from the standard atomic weights of carbon, hydrogen and oxygen, so mg/dL = mmol/L × 18.0156. For example, 5.5 mmol/L × 18.0156 ≈ 99 mg/dL. For HbA1c the NGSP master equation applies: % = 0.09148 × mmol/mol + 2.152, so 48 mmol/mol is 6.5 %. The estimated average glucose comes from the international ADAG study: eAG (mg/dL) = 28.7 × HbA1c (%) − 46.7, so 6.5 % corresponds to about 140 mg/dL, or 7.8 mmol/L.

The conversions of units are exact; the average glucose is a population estimate that can differ for you. The converter does not judge whether a value is normal or high: that depends on when it was measured and on your situation, so ask your doctor.

Frequently asked questions

Why do some countries use mg/dL and others mmol/L?

The United States and several European countries kept the older mass unit, mg/dL, while the United Kingdom, the Nordic countries, Canada and many others use the SI unit mmol/L. The glucose is the same; only the unit differs.

Why do some converters use 18 instead of 18.0156?

18 is a rounded factor. The exact one follows from the molar mass of glucose, 180.156 g/mol. The difference is under 0.1 %, so in practice it changes a result by at most one in the last digit.

Is HbA1c in % the same as a glucose percentage?

No. HbA1c in % is the share of your haemoglobin that has glucose attached. It is a different measure from blood glucose, which is why it needs its own conversion to an estimated average glucose.

Can I convert a glucose reading directly into HbA1c?

No. A single glucose reading and HbA1c measure different things. The HbA1c mode estimates average glucose, not HbA1c from one meter reading.

Do I need to know whether the reading was fasting?

Not for the unit conversion. Fasting status matters when interpreting a result, but does not change the conversion factor.

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