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Convert between A1C and estimated average glucose (eAG) with diabetes ranges.
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A1C Calculator delivers exactly what its name promises, convert between a1c and estimated average glucose (eag) with diabetes ranges, fast and free. Because it belongs to ToolsMonk's medical tools collection, the whole workflow happens on a single page instead of being spread across separate apps or websites.
People reach for it most often when they need your lab report gives an a1c of 6.4% and you want to know what average blood sugar that corresponds to, your meter shows a 14-day average and you want to know roughly what a1c to expect at your next test, and you are comparing a uk or european result in mmol/l against a us result in mg/dl. With nothing to install, an unexpected one-off job takes no longer to start than your regular routine.
It is built for getting a real result on the first visit: no learning curve, no account, and the wider ToolsMonk toolbox close at hand.
| Price | Free, no signup, no paywall, no watermark |
|---|---|
| Works on | Any modern browser: desktop, tablet, and mobile |
| Processing | In your browser, files never leave your device |
| Account required | None |
| Category | Medical Tools |
Choose the direction: A1C to estimated average glucose, or average glucose back to A1C
Type the value from your lab report or meter, or drag the slider if you are exploring
Read the converted figure in both mg/dL and mmol/L, with the ADA category for that A1C
Press Save to keep the reading in a private in-browser log and watch the trend across tests
Converts HbA1c to estimated average glucose using the ADAG study regression: eAG mg/dL = 28.7 x A1C - 46.7
Converts in both directions, so you can enter a meter average and see the A1C it implies
Shows the result in mg/dL and mmol/L using the 18.0182 conversion factor
Classifies the A1C against the ADA thresholds: below 5.7 normal, 5.7 to 6.4 prediabetes, 6.5 and above diabetes
Type an exact lab value or drag the slider, and log results over time to see the trend
Your lab report gives an A1C of 6.4% and you want to know what average blood sugar that corresponds to
Your meter shows a 14-day average and you want to know roughly what A1C to expect at your next test
You are comparing a UK or European result in mmol/L against a US result in mg/dL
You are tracking whether a change in diet, exercise or medication has moved your A1C between tests
A1C Calculator was built so that anyone, professional or first-time visitor, gets what the page promises (convert between a1c and estimated average glucose (eag) with diabetes ranges) in seconds. Results are instant and accurate, and nothing needs to be installed or signed up for along the way.
All processing runs locally in your browser, so your files and data never leave your device. Like every tool in the Medical Tools collection, it works across all modern browsers on desktop, tablet, and mobile: same features, same results, on every device.
HbA1c measures the proportion of your haemoglobin that has glucose attached to it. Because a red blood cell lives roughly 120 days and picks up glucose in proportion to how much is present, the figure works as a slow-moving average of your blood sugar over the preceding two to three months, weighted toward the most recent weeks.
That is useful and also unintuitive, because a percentage of haemoglobin is not a unit anyone thinks in. Estimated average glucose exists to translate it back into the mg/dL or mmol/L a meter shows. The relationship comes from the 2008 ADAG study, which paired A1C values against continuous glucose monitoring and produced the straight line this tool implements: eAG mg/dL = 28.7 x A1C - 46.7.
The ADA category boundaries are 5.7% and 6.5%. They are diagnostic thresholds rather than a smooth risk gradient, which is why a result of 6.4% and one of 6.5% are treated so differently despite being almost the same measurement. Both deserve a conversation with a clinician; neither is decided by a single test.
A1C has real limitations worth knowing. Anything that changes red-blood-cell lifespan changes the result independently of your glucose: iron-deficiency anaemia tends to raise it, haemolysis and recent blood loss tend to lower it, and pregnancy, chronic kidney disease and certain haemoglobin variants all interfere. If your A1C and your meter readings disagree persistently, that gap is itself clinically interesting.
This converter runs entirely in your browser and stores saved readings only on your own device. It applies a published regression to a number you type in: it cannot diagnose anything, does not know your history, and is not a substitute for a laboratory test or the clinician interpreting it.
Enter the exact figure from your lab report rather than rounding it: 6.4 and 6.5 sit either side of a diagnostic threshold
If you are comparing results from different countries, check the units first. A1C is reported as a percentage (NGSP/DCCT) in the US and as mmol/mol (IFCC) in much of Europe, and those are different scales
A single A1C is a two-to-three month summary, so judge a treatment change on the NEXT test, not on daily readings
Save each result here so the trend is visible across tests, which is what a clinician is looking at
Common questions about this tool, its workflow, and what to expect before you use it.
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Convert between A1C and estimated average glucose (eAG) with diabetes ranges.
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