A1C ↔ Average Glucose Converter
Convert between A1C percentage and estimated average glucose (eAG). Uses the ADA-validated regression formula.
How this works
The conversion uses the regression formula derived from the ADAG (A1C-Derived Average Glucose) study:
eAG (mg/dL) = 28.7 × A1C − 46.7 A1C = (eAG + 46.7) / 28.7
During pregnancy, the ADA recommends an A1C target of <6.0% if achievable without significant hypoglycemia, and <6.5% as the more typical clinical target. Note that A1C in pregnancy can underestimate average glucose because of accelerated red-cell turnover — daily glucose monitoring is the more reliable signal in pregnancy than A1C alone.
Source: Nathan DM et al. ADAG Study Group. Diabetes Care 2008. Also: ADA Standards of Care 2026 (see references/clinical-stats.md).
How A1C works during pregnancy
A1C measures the percentage of hemoglobin in your blood that has glucose attached. Because red blood cells live ~3 months, A1C reflects your average glucose over that window — useful for catching trends a single fingerstick can't see.
One catch in pregnancy: red-cell turnover speeds up, so A1C can underestimate your true average glucose by 0.2-0.5%. This is why your obstetrician relies more on daily fingersticks (and increasingly continuous glucose monitors) for day-to-day GD management, with A1C used as a secondary check at intervals.
Pregnancy A1C targets (ADA 2026):
- Ideal: <6.0% if achievable without significant hypoglycemia
- Acceptable: <6.5%
For more on what your A1C actually means alongside daily fingerstick numbers, see our A1C vs daily numbers in GD post.