Tool
HbA1c mmol/mol to % converter
Labs in the UK, Europe and many other countries report HbA1c in mmol/mol. US labs and many guidelines use %. Type either one.
The formula
The NGSP master equation links the two scales (NGSP):
mmol/mol = (% − 2.152) ÷ 0.09148
Average glucose then comes from the ADAG formula, eAG mg/dL = 28.7 × % − 46.7, divided by 18.016 for mmol/L (Nathan 2008).
UK and US ranges are not the same
The diabetes threshold matches: 48 mmol/mol is 6.5% (NGSP). The prediabetes range does not. Diabetes UK uses 42 to 47 mmol/mol (6.0% to 6.4%) (Diabetes UK); the ADA starts at 5.7%, which is 39 mmol/mol (ADA Standards 2026, sec. 2). So a result of 39 to 41 mmol/mol is "prediabetes" by ADA criteria but "normal" by the UK range. Ask your own clinic which range they use.
HbA1c chart: 20 to 130 mmol/mol
| mmol/mol | % | eAG mmol/L | eAG mg/dL | UK range |
|---|---|---|---|---|
| 20 | 4.0 | 3.8 | 68 | Normal |
| 21 | 4.1 | 3.9 | 70 | Normal |
| 22 | 4.2 | 4.0 | 73 | Normal |
| 23 | 4.3 | 4.2 | 75 | Normal |
| 24 | 4.3 | 4.3 | 78 | Normal |
| 25 | 4.4 | 4.5 | 81 | Normal |
| 26 | 4.5 | 4.6 | 83 | Normal |
| 27 | 4.6 | 4.8 | 86 | Normal |
| 28 | 4.7 | 4.9 | 89 | Normal |
| 29 | 4.8 | 5.1 | 91 | Normal |
| 30 | 4.9 | 5.2 | 94 | Normal |
| 31 | 5.0 | 5.4 | 96 | Normal |
| 32 | 5.1 | 5.5 | 99 | Normal |
| 33 | 5.2 | 5.6 | 102 | Normal |
| 34 | 5.3 | 5.8 | 104 | Normal |
| 35 | 5.4 | 5.9 | 107 | Normal |
| 36 | 5.4 | 6.1 | 110 | Normal |
| 37 | 5.5 | 6.2 | 112 | Normal |
| 38 | 5.6 | 6.4 | 115 | Normal |
| 39 | 5.7 | 6.5 | 117 | Normal |
| 40 | 5.8 | 6.7 | 120 | Normal |
| 41 | 5.9 | 6.8 | 123 | Normal |
| 42 | 6.0 | 7.0 | 125 | Prediabetes |
| 43 | 6.1 | 7.1 | 128 | Prediabetes |
| 44 | 6.2 | 7.2 | 131 | Prediabetes |
| 45 | 6.3 | 7.4 | 133 | Prediabetes |
| 46 | 6.4 | 7.5 | 136 | Prediabetes |
| 47 | 6.5 | 7.7 | 138 | Prediabetes |
| 48 | 6.5 | 7.8 | 141 | Diabetes |
| 49 | 6.6 | 8.0 | 144 | Diabetes |
| 50 | 6.7 | 8.1 | 146 | Diabetes |
| 51 | 6.8 | 8.3 | 149 | Diabetes |
| 52 | 6.9 | 8.4 | 152 | Diabetes |
| 53 | 7.0 | 8.6 | 154 | Diabetes |
| 54 | 7.1 | 8.7 | 157 | Diabetes |
| 55 | 7.2 | 8.9 | 159 | Diabetes |
| 56 | 7.3 | 9.0 | 162 | Diabetes |
| 57 | 7.4 | 9.1 | 165 | Diabetes |
| 58 | 7.5 | 9.3 | 167 | Diabetes |
| 59 | 7.5 | 9.4 | 170 | Diabetes |
| 60 | 7.6 | 9.6 | 173 | Diabetes |
| 61 | 7.7 | 9.7 | 175 | Diabetes |
| 62 | 7.8 | 9.9 | 178 | Diabetes |
| 63 | 7.9 | 10.0 | 180 | Diabetes |
| 64 | 8.0 | 10.2 | 183 | Diabetes |
| 65 | 8.1 | 10.3 | 186 | Diabetes |
| 66 | 8.2 | 10.5 | 188 | Diabetes |
| 67 | 8.3 | 10.6 | 191 | Diabetes |
| 68 | 8.4 | 10.7 | 194 | Diabetes |
| 69 | 8.5 | 10.9 | 196 | Diabetes |
| 70 | 8.6 | 11.0 | 199 | Diabetes |
| 71 | 8.6 | 11.2 | 201 | Diabetes |
| 72 | 8.7 | 11.3 | 204 | Diabetes |
| 73 | 8.8 | 11.5 | 207 | Diabetes |
| 74 | 8.9 | 11.6 | 209 | Diabetes |
| 75 | 9.0 | 11.8 | 212 | Diabetes |
| 76 | 9.1 | 11.9 | 215 | Diabetes |
| 77 | 9.2 | 12.1 | 217 | Diabetes |
| 78 | 9.3 | 12.2 | 220 | Diabetes |
| 79 | 9.4 | 12.3 | 222 | Diabetes |
| 80 | 9.5 | 12.5 | 225 | Diabetes |
| 81 | 9.6 | 12.6 | 228 | Diabetes |
| 82 | 9.7 | 12.8 | 230 | Diabetes |
| 83 | 9.7 | 12.9 | 233 | Diabetes |
| 84 | 9.8 | 13.1 | 236 | Diabetes |
| 85 | 9.9 | 13.2 | 238 | Diabetes |
| 86 | 10.0 | 13.4 | 241 | Diabetes |
| 87 | 10.1 | 13.5 | 243 | Diabetes |
| 88 | 10.2 | 13.7 | 246 | Diabetes |
| 89 | 10.3 | 13.8 | 249 | Diabetes |
| 90 | 10.4 | 14.0 | 251 | Diabetes |
| 91 | 10.5 | 14.1 | 254 | Diabetes |
| 92 | 10.6 | 14.2 | 257 | Diabetes |
| 93 | 10.7 | 14.4 | 259 | Diabetes |
| 94 | 10.8 | 14.5 | 262 | Diabetes |
| 95 | 10.8 | 14.7 | 264 | Diabetes |
| 96 | 10.9 | 14.8 | 267 | Diabetes |
| 97 | 11.0 | 15.0 | 270 | Diabetes |
| 98 | 11.1 | 15.1 | 272 | Diabetes |
| 99 | 11.2 | 15.3 | 275 | Diabetes |
| 100 | 11.3 | 15.4 | 278 | Diabetes |
| 101 | 11.4 | 15.6 | 280 | Diabetes |
| 102 | 11.5 | 15.7 | 283 | Diabetes |
| 103 | 11.6 | 15.8 | 285 | Diabetes |
| 104 | 11.7 | 16.0 | 288 | Diabetes |
| 105 | 11.8 | 16.1 | 291 | Diabetes |
| 106 | 11.8 | 16.3 | 293 | Diabetes |
| 107 | 11.9 | 16.4 | 296 | Diabetes |
| 108 | 12.0 | 16.6 | 299 | Diabetes |
| 109 | 12.1 | 16.7 | 301 | Diabetes |
| 110 | 12.2 | 16.9 | 304 | Diabetes |
| 111 | 12.3 | 17.0 | 306 | Diabetes |
| 112 | 12.4 | 17.2 | 309 | Diabetes |
| 113 | 12.5 | 17.3 | 312 | Diabetes |
| 114 | 12.6 | 17.4 | 314 | Diabetes |
| 115 | 12.7 | 17.6 | 317 | Diabetes |
| 116 | 12.8 | 17.7 | 320 | Diabetes |
| 117 | 12.9 | 17.9 | 322 | Diabetes |
| 118 | 12.9 | 18.0 | 325 | Diabetes |
| 119 | 13.0 | 18.2 | 327 | Diabetes |
| 120 | 13.1 | 18.3 | 330 | Diabetes |
| 121 | 13.2 | 18.5 | 333 | Diabetes |
| 122 | 13.3 | 18.6 | 335 | Diabetes |
| 123 | 13.4 | 18.8 | 338 | Diabetes |
| 124 | 13.5 | 18.9 | 341 | Diabetes |
| 125 | 13.6 | 19.1 | 343 | Diabetes |
| 126 | 13.7 | 19.2 | 346 | Diabetes |
| 127 | 13.8 | 19.3 | 348 | Diabetes |
| 128 | 13.9 | 19.5 | 351 | Diabetes |
| 129 | 14.0 | 19.6 | 354 | Diabetes |
| 130 | 14.0 | 19.8 | 356 | Diabetes |
Highlighted: 39 (ADA prediabetes starts), 42 (UK prediabetes starts), 48 (diabetes, both), 53 (7.0%), 64 (8.0%), 75 (9.0%). Want % first? See the A1c chart.
Sources
- NGSP. IFCC Standardization of HbA1c: the IFCC and NGSP master equation (NGSP = 0.09148 x IFCC + 2.152). ngsp.org/ifccngsp.asp
- Diabetes UK. Prediabetes: HbA1c 42 to 47 mmol/mol; type 2 diabetes 48 mmol/mol or above; normal below 42 mmol/mol. www.diabetes.org.uk/about-diabetes/type-2-diabetes/prediabetes
- American Diabetes Association Professional Practice Committee. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1). doi.org/10.2337/dc26-S002
- Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ; A1c-Derived Average Glucose (ADAG) Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31(8):1473-1478. doi.org/10.2337/dc08-0545
Written and maintained by the controla1clevels.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-26. Spotted an error? See About.