# A1c to Average Glucose Calculator (eAG)

URL: https://speedycalculator.com/calculators/health/a1c-to-average-glucose/
Last updated: 2026-10-25

> The A1c calculator converts a hemoglobin A1c percentage into estimated average glucose (eAG) in mg/dL and mmol/L using the ADAG study equation. Type an average glucose to find the matching A1c.

## Inputs

- Hemoglobin A1c (%)

## Results

- Estimated average glucose
- A1c category

## Formula

```
eAG (mg/dL) = 28.7 × A1c − 46.7
```

## Explanation

A1c reflects average blood sugar over about three months. Converting it to glucose units makes it easier to compare with finger-stick readings.

### How to use the A1c to Average Glucose Calculator

- **Hemoglobin A1c**
- Want to work backwards? Type a value into **Estimated average glucose** and **Hemoglobin A1c** is calculated for you.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Multiply A1c by 28.7 and subtract 46.7 for mg/dL; divide by 18 for mmol/L.

### Example values

How the main result changes when **Hemoglobin A1c** changes and everything else stays at the example values above:

Hemoglobin A1c (%)Estimated average glucose (mg/dL)3.5545.2510471548.7520410.525514355
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Hemoglobin A1c: 7 %.

Results — **Estimated average glucose = 154 mg/dL**; A1c category = 7 %.

## Key terms

- **HbA1c**: Glycated haemoglobin, a marker of average glucose.

## FAQ

**What A1c indicates diabetes?**
6.5% or higher on two tests, according to the American Diabetes Association.

**Why might A1c not match my meter?**
Anaemia, recent blood loss and some haemoglobin variants affect A1c.

**What formula does the A1c to Average Glucose Calculator use?**
eAG (mg/dL) = 28.7 × A1c − 46.7.

**Can I work backwards from the result?**
Yes. Type the result you want into Estimated average glucose and the calculator finds the matching hemoglobin a1c.


## Sources

- [Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care, 2008](https://pubmed.ncbi.nlm.nih.gov/18540046/)