HbA1c to average glucose calculator
HbA1c reflects your average blood sugar over about three months. This converts it to an estimated average glucose (eAG) — the same units your glucose meter shows — so the number feels concrete. Enter an A1C, or work backwards from an average glucose.
Estimated average glucose: 125 mg/dL (7 mmol/L)
An estimate from the ADAG regression — not a diagnosis. A lab A1C and a meter reading measure different things; talk to your clinician about your numbers.
The formula
The conversion comes from the A1c-Derived Average Glucose (ADAG) study, which defined the relationship between A1C and average glucose:
- eAG (mg/dL) = 28.7 × A1C − 46.7
- eAG (mmol/L) = 1.59 × A1C − 2.59
Worked example: an A1C of 6.0% → 28.7 × 6.0 − 46.7 ≈ 125 mg/dL (about 7.0 mmol/L). An A1C of 7.0% works out to about 154 mg/dL.
How carb fasting fits
Because HbA1c tracks roughly three months of blood sugar, it's a useful way to see whether an eating change is moving your average over time — though it misses day-to-day swings (a CGM is better for those). See the HbA1c page for the cut points and what they mean, or read the protocol.