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A1C Calculator

Convert A1C to estimated average glucose or estimated average glucose to A1C using the ADA/ADAG relationship.

Enter A1C as a percentage, such as 7.

Used when converting eAG to A1C.

Status: initial

Results

Awaiting calculation

Health education

Introduction

The A1C Calculator converts between A1C percentage and estimated average glucose, also called eAG, using the widely cited ADAG relationship.

The American Diabetes Association describes the estimated average glucose relationship as eAG mg/dL = 28.7 x A1C - 46.7. The reverse formula solves that equation for A1C.

Formula and method guide

A1C to eAG

eAG mg/dL = 28.7 x A1C - 46.7

This estimates average glucose in the same mg/dL unit used by many glucose meters.

eAG to A1C

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

If eAG is entered in mmol/L, the calculator first converts it to mg/dL.

mg/dL to mmol/L

mmol/L = mg/dL / 18.015

This lets the result display both common glucose units.

Variables and cautions

A1C percentage

A lab-reported percentage reflecting glycated hemoglobin.

Estimated average glucose

A calculated estimate intended to be easier to compare with glucose meter units.

mg/dL

Milligrams per deciliter, common in the United States.

mmol/L

Millimoles per liter, common in many other countries.

Range label

A general educational label, not a diagnosis.

FAQs

What does this A1C Calculator calculate?
It converts A1C to estimated average glucose and estimated average glucose to A1C.
What formula is used?
The calculator uses eAG mg/dL = 28.7 x A1C - 46.7 and the reverse formula A1C = (eAG + 46.7) / 28.7.
What is A1C?
A1C is a blood test result reported as a percentage that reflects average blood glucose over roughly the past two to three months.
What is eAG?
eAG means estimated average glucose. It converts A1C into glucose units such as mg/dL or mmol/L.
Is eAG the same as my meter average?
No. eAG is calculated from A1C and may differ from fingerstick or CGM averages.
Can this diagnose diabetes?
No. Diagnosis requires clinical testing and interpretation by a qualified healthcare professional.
What A1C range is commonly considered normal?
Public health references commonly describe below 5.7% as below the prediabetes threshold.
What A1C range is commonly called prediabetes?
Public health references commonly describe 5.7% to 6.4% as the prediabetes range.
What A1C is commonly associated with diabetes?
Public health references commonly describe 6.5% or above as the diabetes threshold, but diagnosis requires clinical evaluation.
Can A1C be inaccurate?
Yes. Conditions affecting red blood cells, hemoglobin variants, pregnancy, kidney disease, and other factors can affect A1C interpretation.
Does this calculator set my target?
No. A1C targets are individualized and should be discussed with a clinician.
Does this replace glucose monitoring?
No. A1C and eAG do not replace glucose monitoring recommended by a healthcare professional.
Can I enter mmol/L?
Yes. Choose mmol/L when converting estimated average glucose to A1C.
Why does 7% A1C show about 154 mg/dL?
Using the formula 28.7 x 7 - 46.7 gives 154.2 mg/dL.
Is this medical advice?
No. It is an educational conversion calculator only.

References

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