Daily Figures Edition No Sign-Up • No Tracking • Free Forever Vol. XII — No. 204
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No. 04 — A1C Calculator

A1C and average glucose, both ways.

Enter an A1C percentage to read your estimated average glucose in mg/dL and mmol/L, or enter a glucose reading to read the A1C it implies. Each result carries a plain interpretation band.

Filed by The Statistics Desk  |  Method: ADAG regression (Nathan et al.)
— or convert the other way —
 
Estimated average glucose
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Conversion readout
A1C glycated haemoglobin—
eAG mg/dL—
eAG mmol/L—
Normal under 5.7%  /  Prediabetes 5.7–6.4%  /  Diabetes 6.5%+ An educational estimate — not medical advice

How the A1C Calculator Works

A1C reflects your average blood glucose over roughly the previous three months. The widely used ADAG study produced a linear relationship between A1C and estimated average glucose, letting you translate one into the other.

The formulas

eAG (mg/dL) = 28.7 × A1C − 46.7

eAG (mmol/L) = 1.59 × A1C − 2.59

A1C = ( eAG mg/dL + 46.7 ) / 28.7

Interpretation bands

A note on use

This tool is for education and quick reference. It does not diagnose anything and does not replace a laboratory test or your clinician's judgement. Individual glucose can vary from the estimate.

Frequently Asked Questions

What does an A1C of 6.5% mean?

An A1C of 6.5 percent or higher is in the diabetes range. It corresponds to an estimated average glucose of about 140 mg/dL. Below 5.7 is normal and 5.7 to 6.4 is prediabetes.

How is estimated average glucose calculated?

The estimated average glucose in mg/dL equals 28.7 times the A1C minus 46.7. In mmol/L it equals 1.59 times the A1C minus 2.59.

Can I convert glucose back to A1C?

Yes. The calculator reverses the formula: A1C equals your average glucose in mg/dL plus 46.7, divided by 28.7.

More From The Desk

Same plain method, different figures