WELLNESS TOOLS
HbA1c and AVERAGE GLUCOSE CALCULATOR
Understand the approximate relationship between average blood glucose and HbA1c. Enter an average glucose value to estimate HbA1c, or enter an HbA1c result to estimate average glucose.
HbA1c is a laboratory blood test that reflects average blood glucose over approximately the previous 2–3 months. A finger-prick reading is a snapshot at one point in time, so it should not be entered as though it were a long-term average.
Important: This is an educational estimate, not a diagnostic test or personalised medical assessment. It cannot diagnose or exclude diabetes, assess remission, determine whether an individual treatment target is being met, or replace a laboratory HbA1c test.
How the calculation works
Three simple steps to explore the relationship between average glucose and HbA1c.
1
Enter Your Value
2
Calculate Your Estimate
3
Understand the Estimate
Enter your average blood glucose in mg/dL or mmol/L, or your known HbA1c result from a laboratory test in mmol/mol or %. Use an average of multiple glucose readings, not a single reading.
Our tool applies the published ADAG population-based formula to convert your value instantly.
See the converted value and general educational context. This is an approximate estimate, not a diagnosis, laboratory result or personalised medical assessment.
This is an approximate population-based estimate, not your measured laboratory result. Individual results can differ. Only a laboratory HbA1c test and appropriate healthcare assessment can assess or diagnose diabetes.
Speak with your GP, diabetes nurse or healthcare team if you are concerned about your glucose or HbA1c. Do not change medication, insulin, diet or exercise based on this calculator.
What does the result mean?
The result shows the mathematical relationship between the number you entered and the converted estimate. It does not show your actual HbA1c unless you entered a laboratory HbA1c result, and it does not replace clinical interpretation.
Understanding UK HbA1c units
UK laboratories generally report HbA1c in mmol/mol. Some websites and devices use the older percentage format, so this calculator allows conversion between the two.
NICE uses HbA1c thresholds when assessing increased risk and possible diabetes, but an online estimate cannot apply those thresholds diagnostically. A healthcare professional must interpret a laboratory result in context.
When to speak to a healthcare professional
Arrange appropriate medical advice if you have symptoms of diabetes, repeated high glucose readings, a concerning laboratory HbA1c, or uncertainty about your result. If you feel seriously unwell, seek urgent medical help rather than relying on this calculator.
Frequently Asked Questions
Everything you need to know about HbA1c
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Disclaimer:
⚠️ This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek guidance from your physician or qualified healthcare provider.