In the Chrome Web StoreA1C Calculator and Blood Sugar Log
Type an A1C result and see the estimated average glucose straight away, or go the other way. Save your results, watch the trend and take a PDF report to your doctor, all in a side panel of your browser.
A free Chrome extension that converts A1C and average glucose and keeps a log of your results.
- % ⇄ mmol/mol
- mg/dL ⇄ mmol/L
- CSV · PDF
How to calculate A1C and eAG
- Click the extension icon. The calculator opens in a side panel.
- Type a value in any field: A1C in % or mmol/mol, or average glucose in mg/dL or mmol/L.
- The other three fields update at once, and the gauge shows the range.
- Pick the date, time and context (fasting, after meal, before bed) and click Save to History.
What it does
Four units, both ways
A1C in % (DCCT) and mmol/mol (IFCC), average glucose in mg/dL and mmol/L. Type in any field and the rest are calculated.
The ADAG formula
Estimated average glucose (eAG) = 28.7 × A1C − 46.7 mg/dL, the relation from the ADAG study used by the American Diabetes Association.
Range at a glance
Below 5.7% is shown as normal, 5.7–6.4% as prediabetes and 6.5% or more as diabetes, the A1C ranges used by the ADA.
Log and trend chart
Save results with a note and context, then view the last 7, 30 or 90 days, the last year, all time or a custom range on a zoomable chart.
CSV, PDF and backup
Export a CSV, a PDF report with summary and chart for a doctor visit, or a JSON backup you can import later.
Reference tables
An A1C conversion table from 5% to 12% and daily glucose targets for fasting, after meals and bedtime.
Screenshots
Your log stays on your computer
Results and settings are stored in your browser only. There is no account and no analytics, and nothing is sent to us.
The calculator gives estimates for information. It is not a medical device and does not replace advice from your doctor.
Questions and answers
How is eAG calculated from A1C?
With the ADAG formula: eAG (mg/dL) = 28.7 × A1C (%) − 46.7. For mmol/L the result is divided by 18.016. For example, an A1C of 7% is about 154 mg/dL or 8.6 mmol/L.
What A1C is prediabetes?
The American Diabetes Association uses 5.7% to 6.4% for prediabetes and 6.5% or higher for diabetes. Your doctor interprets your own results.
How do I convert A1C from % to mmol/mol?
Type the percentage in the A1C (DCCT) field and read the IFCC value next to it, or the other way round.
Can I export my blood sugar log?
Yes. CSV for spreadsheets, a PDF report with summary and chart, and a JSON backup.
Where is my data stored?
Only in your browser on this computer. Make a JSON backup if you want to move it to another device.
Is it free?
Yes. The calculator, log, charts and exports are free.
A1C Calculator
A free Chrome extension that converts A1C and average glucose and keeps a log of your results.
For information only. Not a medical device and not a substitute for professional medical advice.