A1C Units Explained: % vs mmol/mol vs mmol/L
Diabetes management standards vary across the globe. In the United States, A1C is typically reported as a percentage (NGSP units). In Europe and other regions, it is reported in mmol/mol (IFCC units), while daily glucose is measured in mmol/L rather than mg/dL.
International Conversion Math
To convert your A1C percentage to the estimated average glucose (eAG) in mmol/L used internationally:
Step 1: Calculate mg/dL
(28.7 × A1C) − 46.7
Step 2: Convert to mmol/L
Divide by 18.018
Why Do Different Units Exist?
The move toward mmol/mol (IFCC) was designed to standardize lab results globally, as percentages can be less precise in a laboratory setting. However, because patients are most comfortable with the units used on their daily meters, eAG (either in mg/dL or mmol/L) remains the most practical metric for management.
Internal Link: Full Conversion Chart
If you need to see a full range of values at once, visit our Complete A1C to Blood Sugar Chart which includes both US and International units. View the Full Chart here.
