A1C Calculator & Blood Glucose Unit Converter

Estimate your A1C, convert blood sugar units, and convert A1C to average glucose

Conversion

Average blood glucose (mg/dL)

Blood glucose (mg/dL)

Blood glucose (mmol/L)

A1C (%)

Frequently Asked Questions

How do I convert mg/dL to mmol/L? ▼

mmol/L = mg/dL ÷ 18.0182. This conversion factor comes from glucose's molar mass (about 180.16 g/mol) — the US and a few other countries report blood glucose in mg/dL, while most of the world (UK, Canada, Europe) uses mmol/L.

How do I convert mmol/L to mg/dL? ▼

mg/dL = mmol/L × 18.0182. For example, a reading of 7.0 mmol/L converts to about 126 mg/dL.

How is A1C calculated from average glucose? ▼

Using the ADAG study formula solved for A1C: A1C (%) = (average glucose in mg/dL + 46.7) ÷ 28.7. For example, an average glucose of 154 mg/dL corresponds to an estimated A1C of about 7.0%. This is the reverse of the eAG formula below.

What is eAG and how is it calculated from A1C? ▼

eAG (estimated Average Glucose) translates your A1C percentage into the same mg/dL or mmol/L units as a glucose meter, using the ADAG study formula: eAG (mg/dL) = 28.7 × A1C − 46.7. It gives a rough sense of what your daily meter readings have averaged over the past ~3 months.

Is eAG the same as a daily glucose reading? ▼

No — eAG is a 2-3 month average derived from A1C, not a real-time reading. Day-to-day glucose swings (highs after meals, lows between them) can vary widely around this average, so eAG and a single meter reading measure different things.

What are the reference ranges shown with my result? ▼

For a fasting glucose reading, the ADA's published ranges are: normal below 100 mg/dL (5.6 mmol/L), prediabetes 100-125 mg/dL (5.6-6.9 mmol/L), and diabetes 126 mg/dL (7.0 mmol/L) or above. For A1C: normal below 5.7%, prediabetes 5.7-6.4%, and diabetes 6.5% or above. These are general reference ranges, not a diagnosis — only a doctor can interpret your specific result in context.

What is IFCC and how does it relate to A1C%? ▼

IFCC (mmol/mol) is the international laboratory standard unit for A1C, used in most countries outside the US instead of the NGSP % most US labs report. IFCC = (A1C% − 2.15) × 10.929 — for example, an A1C of 7.0% converts to about 53 mmol/mol IFCC.

What is GMI and how is it different from estimated A1C? ▼

GMI (Glucose Management Indicator) is a separate formula developed specifically for continuous glucose monitor (CGM) data: GMI (%) = 3.31 + 0.02392 × mean glucose (mg/dL). It's very close to, but not identical to, the estimated-A1C formula shown above — GMI was derived from a newer, CGM-specific study population, while the classic eAG/A1C formula came from the original ADAG study using periodic blood draws. Neither replaces an actual lab A1C test.