A1C Calculator: A1C to Average Blood Sugar
A1C 7.0% is about 154 mg/dL (8.6 mmol/L). Enter your A1C below to see the estimated average glucose, or go the other way. Nothing you type leaves your browser.
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A range is not a diagnosis. Your care team may set different targets for you.
How it works
- Enter one number. Pick the tab that matches what you have: an A1C percentage, an average glucose, or a lab value in mmol/mol.
- We apply a published formula. The formulas are shown below with their sources, so you can check the math.
- You see where it sits. The marker shows your value against the ranges the American Diabetes Association (ADA) publishes. It is context, not a verdict.
The formulas
A1C to eAG (mg/dL): eAG = 28.7 × A1C − 46.7
Nathan DM et al., Diabetes Care 2008;31:1473 (ADAG study)
mg/dL to mmol/L: divide by 18
Glucose molar mass 180.16 g/mol (mg/dL ÷ 18 = mmol/L)
NGSP % to IFCC mmol/mol: (A1C − 2.152) ÷ 0.09148
NGSP/IFCC master equation (ngsp.org)
What an A1C number tells you
A1C is a blood test that shows the share of your hemoglobin that has sugar attached to it. Because red blood cells live for a few months, the result reflects your average blood sugar over roughly the last two to three months. It is not a snapshot of today.
The ADAG study compared lab A1C with average glucose from frequent measurements, and found a steady line between them. That line is the formula above. It gives an estimated average glucose, written eAG, so that an A1C can be read in the same units as a meter or sensor.
How to read the ranges
The ADA’s Standards of Care list an A1C of 5.7% to 6.4% as the prediabetes range and 6.5% or higher as the diabetes range. In the absence of clear symptoms, a diagnosis needs two abnormal results, which can come from the same blood sample or from different days. The ranges on this page are for context only. If your result is in or near one of them, talk to your doctor about the next step. See what an A1C of 5.7% and an A1C of 6.5% mean.
For many nonpregnant adults who have diabetes, the ADA gives an A1C goal of under 7%. Lower or higher goals can suit some people, depending on health, age and how safe the treatment is. Yours is set with your care team. Read more about an A1C of 7.
Why your meter or sensor may not match
A1C and daily readings answer different questions. A1C smooths over highs and lows, so two people with the same A1C can have very different days. The estimate also assumes an average relationship between A1C and glucose, and some conditions change that relationship, including anemia, some hemoglobin variants, pregnancy and kidney disease treatments. If your A1C and your readings seem to disagree again and again, tell your clinician. People who wear a continuous glucose monitor (CGM) may also see a GMI, which is a different estimate of the same idea. The GMI calculator works it out from your readings.
Using the result well
Bring the number, not a conclusion, to your appointment. Useful questions: What is my A1C goal? How often should I be tested? Does anything about me make A1C less reliable? The ADA suggests testing at least twice a year, and about every three months if goals are not being met or treatment has changed. The A1C chart prints on one page, and how to lower A1C covers what the official sources say helps.
Frequently asked questions
How do you convert A1C to average blood sugar?
Multiply the A1C percentage by 28.7 and subtract 46.7. The result is the estimated average glucose in mg/dL. For example, 7.0% gives about 154 mg/dL. Divide by 18 to get mmol/L.
Is estimated average glucose the same as my meter or CGM average?
Not exactly. The formula describes an average across many people. Your own readings can run higher or lower than the estimate, and the gap is called the glycation gap. If you wear a CGM, its average gives a GMI that can also differ from your lab A1C.
What A1C is normal?
The American Diabetes Association lists an A1C below 5.7% as under the prediabetes range, 5.7% to 6.4% as the prediabetes range, and 6.5% or higher as the diabetes range. Only a clinician can diagnose, and a second test is normally needed to confirm.
Why does my lab report A1C in mmol/mol?
Labs outside the United States often use the IFCC unit, mmol/mol, instead of the NGSP percentage. The conversion is IFCC = (NGSP − 2.152) ÷ 0.09148, so 7.0% is 53 mmol/mol. The third tab converts both ways.
Can I use this to adjust my medicine?
No. This is an information tool. Do not change insulin or any medicine because of a calculation. Talk to your care team about your own targets.
Information only, not medical advice. Your care team may set different targets for you, and only a lab test ordered by a clinician can diagnose diabetes or prediabetes. See our medical disclaimer.
Sources
- Nathan DM et al. Translating the A1C assay into estimated average glucose values (ADAG study). Diabetes Care 2008
- ADA Standards of Care in Diabetes—2026, Section 2: Diagnosis and Classification
- ADA Standards of Care in Diabetes—2026, Section 6: Glycemic Goals
- NGSP: Convert between NGSP and IFCC A1C units
Last reviewed: by the Diabetes Blogs editorial team. Information only, not medical advice.
