A1C calculator: convert A1C and average glucose
This A1C calculator converts your A1C result into estimated average glucose (eAG) in mg/dL and mmol/L and into the IFCC unit mmol/mol. You can also enter your average blood sugar from a meter or CGM and get the matching A1C. The result shows where the value falls: normal, prediabetes or diabetes range.
Example: Value 7 · Unit: A1C in % → A1C: 7.0 %. Source: IFCC = 10.93 × NGSP − 23.50; eAG = 28.7 × A1C − 46.7 (Nathan et al., Diabetes Care 2008), NGSP – Harmonizing Hemoglobin A1c Testing: master equation NGSP/IFCC, ADAG eAG equation, Table 1 (read 09.10.2026). Updated: .
How it is calculated
An A1C of 7% equals an estimated average glucose of 154 mg/dL (8.6 mmol/L) and 53 mmol/mol in IFCC units. A1C measures how much of your hemoglobin has glucose attached and reflects your average blood sugar over the past three months or so.
A1C chart: A1C, average glucose and mmol/mol
| A1C % | mmol/mol | eAG mg/dL | eAG mmol/L |
|---|---|---|---|
| 5.0 | 31 | 97 | 5.4 |
| 5.7 | 39 | 117 | 6.5 |
| 6.0 | 42 | 126 | 7.0 |
| 6.5 | 48 | 140 | 7.8 |
| 7.0 | 53 | 154 | 8.6 |
| 8.0 | 64 | 183 | 10.2 |
| 9.0 | 75 | 212 | 11.8 |
| 10.0 | 86 | 240 | 13.4 |
| 11.0 | 97 | 269 | 14.9 |
| 12.0 | 108 | 298 | 16.5 |
How the A1C calculator works
- Estimated average glucose: eAG (mg/dL) = 28.7 × A1C − 46.7, from the international ADAG study of 507 people. Divide by 18 for mmol/L.
- From average glucose to A1C: A1C = (eAG + 46.7) ÷ 28.7. An average of 154 mg/dL corresponds to about 7.0%.
- IFCC units: mmol/mol = 10.93 × A1C − 23.50, and back: A1C = 0.09148 × mmol/mol + 2.152. 48 mmol/mol is 6.5%.
What do the numbers mean?
For diagnosis, a normal A1C is below 5.7%, 5.7% to 6.4% indicates prediabetes and 6.5% or above indicates diabetes. A diagnosis should be based on a blood sample tested in a lab with an NGSP-certified method, not on a point-of-care test. Your personal A1C goal, if you have diabetes, is set with your health care professional.
Check your weight for your height with the BMI calculator.
Limits
eAG is an estimate: people with the same A1C can have average glucose levels that differ by several mg/dL. Conditions such as anemia or hemoglobin variants, and pregnancy, can make A1C results inaccurate. This calculator does not replace medical advice.
Frequently asked questions
What average blood sugar is an A1C of 7%?
About 154 mg/dL (8.6 mmol/L). An A1C of 6% is about 126 mg/dL and 8% is about 183 mg/dL.
What is a normal A1C?
Below 5.7%. Between 5.7% and 6.4% is prediabetes, and 6.5% or above is in the diabetes range.
How do I convert average glucose to A1C?
A1C = (average glucose in mg/dL + 46.7) ÷ 28.7. For an average of 140 mg/dL that gives about 6.5%.
How do I convert A1C from mmol/mol to percent?
A1C % = 0.09148 × mmol/mol + 2.152. So 53 mmol/mol is 7.0% and 42 mmol/mol is 6.0%.
Why does my meter average differ from my A1C?
eAG comes from a formula fitted to many people, and in the ADAG study people with the same A1C had different average glucose levels. Finger-stick averages also depend on when you test, so a gap of a few mg/dL is normal.
Sources and legal basis
- IFCC = 10.93 × NGSP − 23.50; eAG = 28.7 × A1C − 46.7 (Nathan et al., Diabetes Care 2008): NGSP – Harmonizing Hemoglobin A1c Testing: master equation NGSP/IFCC, ADAG eAG equation, Table 1 (read 09.10.2026)
- NIDDK – The A1C Test & Diabetes: normal below 5.7%, prediabetes 5.7–6.4%, diabetes 6.5% or above (read 09.10.2026)
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