Diabetes & metabolism

HbA1c unit converter

Long-term blood sugar (glycated hemoglobin)

Also known as: A1c, Hemoglobin A1c, Haemoglobin A1c, Glycated hemoglobin, Glycated haemoglobin, Glycosylated hemoglobin

Converter

Enter a value in any unit and all other units fill in.

% mmol/mol

Worked example

4.8 % (middle of the reference range) = 28.9 mmol/mol

Conversion formulas

mmol/mol	mmol/mol = % × 10.93 − 23.52	% = (mmol/mol + 23.52) × 0.09148

Reference range

Unit	Adults
%	4 – 5.6
mmol/mol	20.2 – 37.69

Source: NIDDK (NIH): Diagnostic tests for diabetes and prediabetes · Last reviewed: 2026-10-14

Note from the source: A1C normal below 5.7%, prediabetes 5.7-6.4%, diabetes 6.5% or above (NIDDK, same as ADA). The lower limit 4.0% is the usual laboratory limit of healthy adults

Frequently asked questions

How do I convert HbA1c from % to mmol/mol?

mmol/mol = % × 10.93 − 23.52. In the other direction: % = (mmol/mol + 23.52) × 0.09148.

What is the reference range of HbA1c?

For adults the range is 4 – 5.6 % (NIDDK (NIH): Diagnostic tests for diabetes and prediabetes). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for HbA1c?

Common units are %, mmol/mol.