A1C Calculator
A1C calculator: converts A1C to estimated average glucose (eAG) and back in mg/dL or mmol/L with the ADA formula, 28.7 × A1C − 46.7, plus IFCC mmol/mol. How it works
Use the A1C Calculator
About the A1C Calculator
An A1C of 7% equals an estimated average glucose (eAG) of 154 mg/dL, or 8.6 mmol/L, and 53 mmol/mol in IFCC units. The formula is eAG in mg/dL = 28.7 × A1C − 46.7, from the ADAG study the American Diabetes Association uses. This A1C calculator converts in either direction and names the ADA range the A1C falls in. It does not diagnose anything.
A1C to average glucose (eAG) chart
| A1C | eAG in mg/dL | eAG in mmol/L | IFCC |
|---|---|---|---|
| 5.0% | 97 mg/dL | 5.4 mmol/L | 31 mmol/mol |
| 5.5% | 111 mg/dL | 6.2 mmol/L | 37 mmol/mol |
| 6.0% | 126 mg/dL | 7.0 mmol/L | 42 mmol/mol |
| 6.5% | 140 mg/dL | 7.8 mmol/L | 48 mmol/mol |
| 7.0% | 154 mg/dL | 8.6 mmol/L | 53 mmol/mol |
| 7.5% | 169 mg/dL | 9.4 mmol/L | 58 mmol/mol |
| 8.0% | 183 mg/dL | 10.2 mmol/L | 64 mmol/mol |
| 8.5% | 197 mg/dL | 10.9 mmol/L | 69 mmol/mol |
| 9.0% | 212 mg/dL | 11.7 mmol/L | 75 mmol/mol |
| 9.5% | 226 mg/dL | 12.5 mmol/L | 80 mmol/mol |
| 10.0% | 240 mg/dL | 13.3 mmol/L | 86 mmol/mol |
| 10.5% | 255 mg/dL | 14.1 mmol/L | 91 mmol/mol |
| 11.0% | 269 mg/dL | 14.9 mmol/L | 97 mmol/mol |
| 11.5% | 283 mg/dL | 15.7 mmol/L | 102 mmol/mol |
| 12.0% | 298 mg/dL | 16.5 mmol/L | 108 mmol/mol |
The mg/dL column matches the ADA’s published table from 6% to 10%. The mmol/L column is mg/dL ÷ 18.016, and the ADA’s table prints four cells 0.1 differently: 10.1 at 8%, 11.8 at 9%, 12.6 at 9.5% and 13.4 at 10%.
Average glucose in mg/dL to A1C
| Average glucose | In mmol/L | A1C | IFCC |
|---|---|---|---|
| 100 mg/dL | 5.6 mmol/L | 5.1% | 32 mmol/mol |
| 110 mg/dL | 6.1 mmol/L | 5.5% | 37 mmol/mol |
| 120 mg/dL | 6.7 mmol/L | 5.8% | 40 mmol/mol |
| 130 mg/dL | 7.2 mmol/L | 6.2% | 44 mmol/mol |
| 140 mg/dL | 7.8 mmol/L | 6.5% | 48 mmol/mol |
| 150 mg/dL | 8.3 mmol/L | 6.9% | 52 mmol/mol |
| 160 mg/dL | 8.9 mmol/L | 7.2% | 55 mmol/mol |
| 170 mg/dL | 9.4 mmol/L | 7.6% | 60 mmol/mol |
| 180 mg/dL | 10 mmol/L | 7.9% | 63 mmol/mol |
| 200 mg/dL | 11.1 mmol/L | 8.6% | 70 mmol/mol |
| 220 mg/dL | 12.2 mmol/L | 9.3% | 78 mmol/mol |
| 250 mg/dL | 13.9 mmol/L | 10.3% | 89 mmol/mol |
| 300 mg/dL | 16.7 mmol/L | 12.1% | 109 mmol/mol |
What the calculator shows when the figure in the first column is typed into the glucose box. The figure has to be an average over about three months for the conversion to mean anything.
Average glucose in mmol/L to A1C
| Average glucose | In mg/dL | A1C | IFCC |
|---|---|---|---|
| 5 mmol/L | 90 mg/dL | 4.8% | 29 mmol/mol |
| 6 mmol/L | 108 mg/dL | 5.4% | 36 mmol/mol |
| 7 mmol/L | 126 mg/dL | 6.0% | 42 mmol/mol |
| 8 mmol/L | 144 mg/dL | 6.6% | 49 mmol/mol |
| 9 mmol/L | 162 mg/dL | 7.3% | 56 mmol/mol |
| 10 mmol/L | 180 mg/dL | 7.9% | 63 mmol/mol |
| 11 mmol/L | 198 mg/dL | 8.5% | 69 mmol/mol |
| 12 mmol/L | 216 mg/dL | 9.2% | 77 mmol/mol |
| 13 mmol/L | 234 mg/dL | 9.8% | 84 mmol/mol |
| 14 mmol/L | 252 mg/dL | 10.4% | 90 mmol/mol |
| 15 mmol/L | 270 mg/dL | 11.0% | 97 mmol/mol |
With the unit switch set to mmol/L. A1C is rounded to one decimal, and the IFCC value is worked out from that rounded A1C.
Methodology
eAG in mg/dL = 28.7 × A1C − 46.7, the regression from the A1c-Derived Average Glucose (ADAG) study. In reverse, A1C = (eAG + 46.7) ÷ 28.7, rounded to one decimal. mmol/L = mg/dL ÷ 18.016, from the molar mass of glucose, 180.16 g/mol. IFCC in mmol/mol = (A1C − 2.15) × 10.929, which reproduces the NGSP conversion table. The calculator accepts A1C from 3% to 20%, or the matching glucose range of 40 to 527 mg/dL.
How to use this tool
- Pick the glucose unit, mg/dL or mmol/L.
- Type in either box: an A1C percentage, or an average glucose. The other box follows.
- Read the result in all four forms, and the ADA range named under it.
Frequently asked questions
- What average blood sugar is an A1C of 6.5?
- 140 mg/dL, or 7.8 mmol/L. For comparison, 5.7% is 117 mg/dL, 8.0% is 183 mg/dL and 9.0% is 212 mg/dL. Each whole point of A1C adds 28.7 mg/dL to the estimated average.
- How do I convert average glucose to A1C?
- A1C = (average glucose in mg/dL + 46.7) ÷ 28.7. An average of 150 mg/dL gives 6.9% and 200 mg/dL gives 8.6%; in mmol/L, 8 gives 6.6% and 10 gives 7.9%. The average has to cover about three months. In the study behind the formula each person contributed about 2,700 readings from continuous monitors and fingersticks, which a few meter readings cannot stand in for.
- What A1C is prediabetes or diabetes?
- The American Diabetes Association puts prediabetes at an A1C of 5.7% to 6.4% and says diabetes is diagnosed at 6.5% or higher. It also says a test usually has to be repeated on a second day. The calculator names the range a number falls in and stops there: a diagnosis takes a lab test and a clinician.
- How accurate is estimated average glucose?
- It is a regression estimate. The ADAG study followed 507 people, 268 with type 1 diabetes, 159 with type 2 and 80 without diabetes, and the line explained 84% of the variation in their measured averages (R² = 0.84). Two people with the same A1C can therefore have different averages. NIDDK also notes that some hemoglobin variants make an A1C result falsely high or low, depending on the lab method.
- What is my A1C in mmol/mol?
- IFCC units are (A1C − 2.15) × 10.929. An A1C of 6.5% is 48 mmol/mol, 7% is 53 and 8% is 64. The whole-percent values match the conversion table published by the NGSP, the US program that standardizes A1C testing.
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