GlucoCalc

A1C Calculator

Convert A1C percentage to the average blood sugar it represents.

A1C (%)

Estimated average glucose

117 mg/dL

6.5 mmol/L

Category: Prediabetes

What you entered

A1C: 5.7%

1
Estimated average glucose (eAG)
28.7 × 5.7 − 46.7= 117 mg/dL
2
Convert to mmol/L
117 ÷ 18= 6.5 mmol/L
3
A1C category
5.7% → 5.7–6.4%= Prediabetes

Result

eAG: 117 mg/dL

An A1C of 5.7% corresponds to an estimated average glucose of 117 mg/dL (6.5 mmol/L). This falls in the "Prediabetes" range.

HbA1c converted to estimated average glucose

The ADAG equation converts an HbA1c percentage into estimated average glucose: 28.7 times A1c minus 46.7, in mg/dL.

HbA1c	Average glucose (mg/dL)	Average glucose (mmol/L)	Category
5.0%	96.8	5.4	Normal
5.7%	116.9	6.5	Prediabetes
6.0%	125.5	7.0	Prediabetes
6.5%	139.8	7.8	Diabetes
7.0%	154.2	8.6	Diabetes
8.0%	182.9	10.2	Diabetes
9.0%	211.6	11.8	Diabetes
10.0%	240.3	13.4	Diabetes

HbA1c reflects roughly the last three months of blood glucose. Diagnostic thresholds are 5.7% for prediabetes and 6.5% for diabetes, but anaemia, pregnancy, and some haemoglobin variants distort the reading. Diagnosis and treatment targets are a clinician's call. General wellness information only, not medical advice. Discuss any health decision with a qualified clinician.

What A1C measures

A1C (glycated hemoglobin) reflects your average blood sugar over the past 2-3 months. Glucose attaches to hemoglobin in red blood cells; the higher your blood sugar, the more hemoglobin gets glycated. Normal is below 5.7%, prediabetes is 5.7-6.4%, and diabetes is 6.5% or higher.

The eAG conversion formula

The ADAG study established eAG (mg/dL) = 28.7 × A1C − 46.7. For example, an A1C of 7% translates to an average glucose of ~154 mg/dL. This lets patients relate their lab A1C to the daily numbers they see on their glucose meter.

Frequently asked questions

What is a normal A1C level?

Normal: below 5.7%. Prediabetes: 5.7–6.4%. Diabetes: 6.5% or higher. For diagnosed diabetics, the ADA recommends a target of <7% for most adults (corresponding to an average glucose of ~154 mg/dL). Tighter control (<6.5%) may be appropriate for some; looser targets (<8%) for others with complications or hypoglycemia risk.

How can I lower my A1C?

Each 1% drop in A1C reduces risk of diabetic complications by ~10–25%. Strategies: reduce refined carbs and sugar, increase fiber intake, exercise 150+ min/week (lowers A1C by 0.5–0.7%), lose 5–7% of body weight if overweight, take medications as prescribed, and monitor blood sugar regularly. Most people see results within 2–3 months.

How often should A1C be tested?

For diabetics: every 3 months if treatment is changing or targets aren't met, every 6 months if stable and at target. For prediabetics: annually. For screening: the ADA recommends testing all adults starting at age 35, or earlier with risk factors (overweight, family history, certain ethnicities, gestational diabetes history).