How to Calculate A1C to Blood Sugar
What is A1C to Blood Sugar?
HbA1c measures average blood glucose over 2–3 months. The eAG conversion gives results in everyday mg/dL or mmol/L units for comparison with daily readings.
Formula
eAG (mg/dL) = 28.7 × HbA1c% − 46.7; eAG (mmol/L) = 1.59 × HbA1c − 2.59
- HbA1c
- Hemoglobin A1c percentage (Percentage (4–14% typical range))
- eAG
- Estimated average glucose (mg/dL or mmol/L)
Step-by-Step Guide
- 1eAG (mg/dL) = 28.7 × A1c% − 46.7
- 2eAG (mmol/L) = eAG(mg/dL) / 18.018
- 3Normal < 5.7%; Prediabetes 5.7–6.4%; Diabetes ≥ 6.5%
- 4Each 1% A1c ≈ 28.7 mg/dL change in average glucose
Worked Examples
Input
A1c = 7.0%
Result
eAG = 154 mg/dL (8.6 mmol/L) — Diabetes
Frequently Asked Questions
What does HbA1c measure?
Average blood glucose over 2–3 months. Red blood cells carry glucose-attached hemoglobin; the ratio reflects long-term average. More reliable than single glucose reading.
What HbA1c is considered diabetic?
< 5.7% = normal; 5.7–6.4% = prediabetic; ≥ 6.5% = diabetic. Goal for most diabetics: < 7% (some target < 6.5%). Individual targets vary by age/comorbidities.
How often should I test?
Non-diabetic: baseline only. Prediabetic: annually. Diabetic: 2–4 times/year depending on control. More frequent if changing treatment or poorly controlled.
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