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Blood Sugar Converter and HbA1c Calculator

Convert a blood sugar reading between mg/dL and mmol/L, see whether it's normal, prediabetes or in the diabetes range, and turn an HbA1c result into your average sugar.

Rules last checked 25 October 2026Every step shown

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In mmol/L

6.1 mmol/L

Fasting reading
Prediabetes

110 mg/dL is 6.1 mmol/L. As a fasting reading that's prediabetes.

How it's worked out

  1. Convert110 ÷ 186.1 mmol/L
  • Fasting: under 100 mg/dL (5.6 mmol/L) is normal, 100 to 125 prediabetes, 126 or more the diabetes range. Below 70 mg/dL (3.9 mmol/L) is low: take sugar and get help if you feel unwell.

The formulas

mmol/L = mg/dL ÷ 18 · Average glucose (mg/dL) = 28.7 × HbA1c − 46.7

Worked examples

A fasting sugar of 110 mg/dL is 6.1 mmol/L, in the prediabetes range. An HbA1c of 6.8% means an average sugar of about 148 mg/dL.

This explains a reading; it can't diagnose. See a doctor about any result outside the normal range.

Questions people ask

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

Divide by 18. A fasting reading of 110 mg/dL is 6.1 mmol/L.

What is a normal fasting blood sugar?

Under 100 mg/dL (5.6 mmol/L). 100 to 125 is prediabetes, and 126 or more on two tests is diabetes (American Diabetes Association).

What does HbA1c 6.8% mean?

An average blood sugar of about 148 mg/dL (8.2 mmol/L) over the last 2 to 3 months, which is in the diabetes range (6.5% or more).

Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem