🏃 Health & Fitness
A1C Calculator
HbA1c reflects average blood glucose over the previous two to three months, because it measures how much glucose has stuck to haemoglobin — and red blood cells live about that long. The conversion is a straight line fitted to continuous glucose monitoring data, so it is an estimate rather than a measurement.
How it works
HbA1c
Estimated average glucose
Estimated average glucose
HbA1c
Frequently asked questions
How do I use the A1C Calculator?
Fill in the fields above — the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.