Convert HbA1c between percentage, mmol/mol and estimated average glucose.
HbA1c reflects average glucose over the red cell lifespan, so it lags recent changes by weeks. The two reporting units express the same measurement and convert linearly. HbA1c can be misleading where red cell turnover is abnormal, such as in anaemia or pregnancy, which is why it is interpreted alongside direct glucose measurement.
A1c to Average Glucose
eAG (mg/dL) = 28.7 × A1c − 46.7; IFCC (mmol/mol) = (A1c − 2.15) × 10.929
This reproduces a published formula for educational and reference use only. It is not a diagnostic tool, does not account for individual clinical context, and must not be used to make or change treatment decisions. Clinical assessment by a qualified healthcare professional is always required. Reference bands quoted here are general and vary between guidelines and laboratories. Interpretation of HbA1c requires clinical context and must be done by a healthcare professional.
eAG (mg/dL) = 28.7 × A1c − 46.7; IFCC (mmol/mol) = (A1c − 2.15) × 10.929 HbA1c reflects average glucose over the red cell lifespan, so it lags recent changes by weeks. The two reporting units express the same measurement and convert linearly.
HbA1c can be misleading where red cell turnover is abnormal, such as in anaemia or pregnancy, which is why it is interpreted alongside direct glucose measurement.
This calculator takes 1 input: HbA1c. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.