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Glucose.mu

Converter

A1c Converter

Lab reports mix three languages for the same number: HbA1c in percent, HbA1c in mmol/mol, and the estimated average glucose it corresponds to. Enter whichever one your report shows and read the other two, using the published ADAG relationship.
My report shows HbA1c in

Most reports show a value between about 4 and 14 percent.

The same number, three ways

Enter your HbA1c and choose Convert. Nothing you type leaves this page.

Sources

  1. eAG/A1C conversion American Diabetes AssociationSource of the eAG relationship and the reference category conventions.
  2. Translating the A1C assay into estimated average glucose values Nathan DM et al, Diabetes Care, 2008
  3. IFCC and NGSP unit conversion NGSP (National Glycohemoglobin Standardization Program)

Last reviewed: 2026-07-16

What HbA1c actually measures

Glucose in the blood slowly and irreversibly attaches to haemoglobin inside red blood cells. Because those cells live about three months, the fraction of haemoglobin that carries glucose, which is what HbA1c reports, works like a flight recorder of your average glucose over the past two to three months. That is why it cannot be gamed by a good day before the test, and also why it hides the day-to-day swings a CGM would show.

The three-language confusion is historical: older studies and most conversation use percent, modern laboratories increasingly report mmol/mol, and clinicians often translate both into an estimated average glucose because milligrams per decilitre feels more tangible. They are one measurement wearing three outfits, and the converter above simply changes the clothes.