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HbA1c chart: normal, prediabetes and diabetes ranges

Updated October 31, 2026 · 15 sources · Written by the AumniVIDA team

Units

Short answer

A normal HbA1c is below 5.7% (39 mmol/mol)39 mmol/mol (5.7%). Prediabetes is 5.7 to 6.4% (39 to 47 mmol/mol)39 to 47 mmol/mol (5.7 to 6.4%), and 6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher is in the diabetes range, confirmed by a second test. These ADA thresholds apply at every age; NICE starts its high-risk range at 6.0% (42 mmol/mol)42 mmol/mol (6.0%) .

HbA1c ranges in percent: normal, prediabetes and diabetes

NormalPrediabetesDiabetes rangeNormal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Normal: 4 to 5.7 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Prediabetes: 5.7 to 6.5 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %Diabetes range: 6.5 to 9 %45.7ADA prediabetes: 5.7 %6NICE and IEC high risk: 6 %6.5ADA and WHO diagnosis: 6.5 %7ADA goal for many with diabetes: 7 %9 %
Normal
4 to 5.7
Prediabetes
5.7 to 6.5
Diabetes range
6.5 to 9
  • 5.7 %: ADA prediabetes
  • 6 %: NICE and IEC high risk
  • 6.5 %: ADA and WHO diagnosis
  • 7 %: ADA goal for many with diabetes
ADA calls 5.7 to 6.4% prediabetes; ADA and WHO both diagnose diabetes from 6.5%, and NICE and the IEC flag high risk from 6.0%.

Key takeaways

  1. 1

    Normal: below 5.7% (39 mmol/mol)39 mmol/mol (5.7%); prediabetes: 5.7 to 6.4% (39 to 47 mmol/mol)39 to 47 mmol/mol (5.7 to 6.4%); diabetes range: 6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher [1].

  2. 2

    NICE and the International Expert Committee set the high-risk range at 6.0 to 6.4% (42 to 47 mmol/mol)42 to 47 mmol/mol (6.0 to 6.4%) [2] [3].

  3. 3

    Convert with mmol/mol = 10.929 x (A1c % minus 2.15) [4]; estimate average glucose with eAG = 28.7 x A1c minus 46.7 mg/dL [5].

  4. 4

    A1c rises about 0.01 points per year of age, but diagnostic thresholds are not age-specific [6].

  5. 5

    For many adults with diabetes, ADA suggests a goal below 7% (53 mmol/mol)53 mmol/mol (7%) [7].

What is a normal A1c level?

By ADA criteria, a normal A1c is below 5.7% (39 mmol/mol)39 mmol/mol (5.7%). NICE uses below 6.0% (42 mmol/mol)42 mmol/mol (6.0%) as the cut-off for high risk, and WHO sets no formal category below 6.5% [1] [2] [8].

The ADA threshold of 5.7% was chosen because it is more specific than the fasting glucose cut-off for identifying people who go on to develop diabetes [9].

Normal does not mean risk-free. In the ARIC study, adults at 5.5 to 5.9% had 1.86 times the diabetes risk of those at 5.0 to 5.4% [10]. Risk rises steadily across the range rather than switching on at one number [1].

What A1c levels mean prediabetes and diabetes?

ADA defines prediabetes as 5.7 to 6.4% (39 to 47 mmol/mol)39 to 47 mmol/mol (5.7 to 6.4%) and diabetes as 6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher. WHO, NICE and the International Expert Committee use the same 6.5% diagnostic threshold [1] [8].

The diabetes threshold of 6.5% came from the point at which moderate retinopathy becomes clearly more common [3]. The prediabetes range is where guidelines disagree: ADA starts at 5.7% [1], while NICE and the International Expert Committee start at 6.0% [2] [3], and WHO declined to set a lower category [8].

A single result in the diabetes range is not a diagnosis. ADA asks for two abnormal results, from the same test repeated or two different tests, unless there are clear symptoms with a random glucose of 200 mg/dL or more [1]. The high A1c page explains what each range means and what to do next.

HbA1c thresholds by guideline, in % (NGSP/DCCT) and mmol/mol (IFCC)
CategoryADA Standards of Care 2026WHO 2011NICE PH38International Expert Committee 2009
NormalBelow 5.7% (below 39 mmol/mol)No formal threshold below 6.5%Below 6.0% (below 42 mmol/mol)No lower threshold set
Raised riskPrediabetes: 5.7 to 6.4% (39 to 47 mmol/mol)39 to 47 mmol/mol (5.7 to 6.4%)Insufficient evidence for a formal categoryHigh risk: 6.0 to 6.4% (42 to 47 mmol/mol)42 to 47 mmol/mol (6.0 to 6.4%)6.0 to 6.4% (42 to 47 mmol/mol)42 to 47 mmol/mol (6.0 to 6.4%): offer prevention
Diabetes6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher, confirmed6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher, second test6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher, repeat test
Goal with diabetesBelow 7% (53 mmol/mol)53 mmol/mol (7%) for many adultsNot coveredNot coveredNot covered

HbA1c ranges in mmol/mol (IFCC units)

NormalPrediabetesDiabetes rangeNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molNormal: 20 to 39 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molPrediabetes: 39 to 48 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/molDiabetes range: 48 to 75 mmol/mol2039ADA prediabetes: 39 mmol/mol42NICE high risk: 42 mmol/mol48Diagnosis: 48 mmol/mol53ADA goal for many with diabetes: 53 mmol/mol75 mmol/mol
Normal
20 to 39
Prediabetes
39 to 48
Diabetes range
48 to 75
  • 39 mmol/mol: ADA prediabetes
  • 42 mmol/mol: NICE high risk
  • 48 mmol/mol: Diagnosis
  • 53 mmol/mol: ADA goal for many with diabetes
In IFCC units, prediabetes starts at 39 mmol/mol (ADA) or 42 mmol/mol (NICE), and the diabetes threshold is 48 mmol/mol.

A1c chart from 4% to 14%

The chart below converts each A1c to mmol/mol and to estimated average glucose. For example, 6.5% is 48 mmol/mol and about 140 mg/dL (7.8 mmol/L)7.8 mmol/L (140 mg/dL); 8% is 64 mmol/mol and about 183 mg/dL [5] [4].

The mmol/mol column uses the IFCC to NGSP relationship from the 2004 method-comparison study [4]. The average glucose columns use the ADAG regression, eAG (mg/dL) = 28.7 x A1c minus 46.7 and eAG (mmol/L) = 1.5944 x A1c minus 2.594 [5].

Two cautions. First, ADAG published estimates for 5% to 12%; values outside that range extend the same formula. Second, each average glucose is a central estimate: at 7%, the 95% range of true averages ran from 123 to 185 mg/dL [5]. The average glucose page shows the spread for every value.

HbA1c chart: % to mmol/mol and estimated average glucose (ADAG formula) [5]
A1c (%)A1c (mmol/mol)eAG (mg/dL)eAG (mmol/L)ADA category
4.0%20683.8Below the prediabetes range
4.5%26824.6Below the prediabetes range
5.0%31975.4Below the prediabetes range
5.5%371116.2Below the prediabetes range
5.7%391176.5Prediabetes range (ADA)
6.0%421257.0Prediabetes range (ADA)
6.5%481407.8Diabetes range (ADA, WHO)
7.0%531548.6Diabetes range (ADA, WHO)
7.5%581699.4Diabetes range (ADA, WHO)
8.0%6418310.2Diabetes range (ADA, WHO)
8.5%6919711.0Diabetes range (ADA, WHO)
9.0%7521211.8Diabetes range (ADA, WHO)
9.5%8022612.6Diabetes range (ADA, WHO)
10.0%8624013.4Diabetes range (ADA, WHO)
10.5%9125514.1Diabetes range (ADA, WHO)
11.0%9726914.9Diabetes range (ADA, WHO)
11.5%10228315.7Diabetes range (ADA, WHO)
12.0%10829816.5Diabetes range (ADA, WHO)
12.5%11331217.3Diabetes range (ADA, WHO)
13.0%11932618.1Diabetes range (ADA, WHO)
13.5%12434118.9Diabetes range (ADA, WHO)
14.0%13035519.7Diabetes range (ADA, WHO)

What is a normal A1c by age?

A1c rises slightly with age, about 0.01 points per year in adults without diabetes, but guidelines use the same thresholds at every age. The upper normal limit (97.5th percentile) was 5.6 to 6.0% under age 40 and 6.2 to 6.6% at 70 and over [6].

In the Framingham Offspring Study and NHANES, A1c increased by 0.014 and 0.010 points per year in people without diabetes, even after excluding anyone with impaired fasting glucose or glucose tolerance [6]. The authors raised the question of age-specific criteria, but no major guideline has adopted them [1].

Treatment goals do change with age and health. ADA suggests below 7% (53 mmol/mol)53 mmol/mol (7%) for many nonpregnant adults with diabetes and sets goals individually, which often means less strict goals for older adults at risk of hypoglycemia [7]. Guidelines do not set different A1c ranges for men and women.

If you are older and your A1c sits just above 5.7%, part of the rise may simply reflect age [6]. That is a reason to look at the trend and at other markers, such as fasting glucose, rather than at a single result.

How do you convert A1c between % and mmol/mol?

Use mmol/mol = 10.929 x (A1c % minus 2.15), or A1c % = mmol/mol / 10.929 + 2.15. The formula comes from the method-comparison study that linked the IFCC reference method to the US NGSP scale [4].

The two units measure the same thing on different scales. The NGSP percent is traceable to the assay used in the DCCT, so it carries the meaning of the big outcome trials [11]. The IFCC unit counts glycated hemoglobin molecules per 1,000 hemoglobin molecules using a more specific reference method, which is why its numbers are not simply 10 times the percent [4].

Landmarks worth memorizing:

  • 5.7% is 39 mmol/mol (ADA prediabetes) [1]
  • 6.0% is 42 mmol/mol (NICE high risk) [2]
  • 6.5% is 48 mmol/mol (diabetes threshold) [8]
  • 7.0% is 53 mmol/mol (ADA goal for many adults with diabetes) [7]

Because the scales are not proportional, a change of 1 percentage point equals about 11 mmol/mol, and 1 mmol/mol equals about 0.09 points [4].

What A1c goal do guidelines set for people with diabetes?

ADA suggests an A1c goal below 7% (53 mmol/mol)53 mmol/mol (7%) for many nonpregnant adults with diabetes, adjusted for hypoglycemia risk and health. In pregnancy the ideal goal is below 6% (42 mmol/mol)42 mmol/mol (6%) if reachable without significant hypoglycemia [7] [12].

These goals rest on the trials that tied lower A1c to fewer complications. In UKPDS, each 1 point lower A1c was associated with 37% fewer microvascular complications [13]. Intensive control also brings more hypoglycemia, which is why goals are set for each person rather than pushed as low as possible [14] [7].

ADA also suggests a CGM goal of more than 70% time in range for many adults who use CGM [7] [15].

More about HbA1c

Protocols that act on HbA1c

Common questions

Is an A1c of 5.5 good?

An A1c of 5.5% (37 mmol/mol)37 mmol/mol (5.5%) is in the normal range by every major guideline [1]. In ARIC, risk of future diabetes was higher at 5.5 to 5.9% than at 5.0 to 5.4%, so it sits at the upper part of normal [10].

Is an A1c of 5.7 bad?

An A1c of 5.7% (39 mmol/mol)39 mmol/mol (5.7%) is the lower edge of the ADA prediabetes range [1]. It signals raised risk, not disease, and NICE would still class it as below its high-risk range [2].

What A1c level is considered diabetic?

An A1c of 6.5% (48 mmol/mol)48 mmol/mol (6.5%) or higher is in the diabetes range under ADA, WHO and NICE criteria, confirmed by a second test unless symptoms are clear [1] [8].

What are A1c units in the UK?

The UK reports HbA1c in mmol/mol (IFCC units). Convert with mmol/mol = 10.929 x (% minus 2.15), so 48 mmol/mol equals 6.5% [4] [2].

Are A1c ranges different for women and men?

No. Guidelines use the same thresholds for everyone; the main exception is pregnancy, where A1c runs slightly lower and glucose tests are preferred for diagnosis [1] [12].

Sources

  1. 1.American Diabetes Association Professional Practice Committee for Diabetes. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2026. Diabetes Care, 2026. doi:10.2337/dc26-S002
  2. 2.National Institute for Health and Care Excellence. Type 2 diabetes: prevention in people at high risk (PH38). NICE public health guideline, 2012. Link
  3. 3.International Expert Committee. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care, 2009. doi:10.2337/dc09-9033
  4. 4.Hoelzel W, Weykamp C, Jeppsson JO, et al. IFCC reference system for measurement of hemoglobin A1c in human blood and the national standardization schemes in the United States, Japan, and Sweden: a method-comparison study. Clinical Chemistry, 2004. doi:10.1373/clinchem.2003.024802
  5. 5.Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ; A1c-Derived Average Glucose Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care, 2008. doi:10.2337/dc08-0545
  6. 6.Pani LN, Korenda L, Meigs JB, et al. Effect of aging on A1C levels in individuals without diabetes: evidence from the Framingham Offspring Study and the National Health and Nutrition Examination Survey 2001-2004. Diabetes Care, 2008. doi:10.2337/dc08-0577
  7. 7.American Diabetes Association Professional Practice Committee for Diabetes. 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes-2026. Diabetes Care, 2026. doi:10.2337/dc26-S006
  8. 8.World Health Organization. Use of glycated haemoglobin (HbA1c) in diagnosis of diabetes mellitus: abbreviated report of a WHO consultation. World Health Organization, 2011. Link
  9. 9.American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care, 2010. doi:10.2337/dc10-S062
  10. 10.Selvin E, Steffes MW, Zhu H, et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. New England Journal of Medicine, 2010. doi:10.1056/NEJMoa0908359
  11. 11.Little RR, Rohlfing CL, Wiedmeyer HM, Myers GL, Sacks DB, Goldstein DE. The national glycohemoglobin standardization program: a five-year progress report. Clinical Chemistry, 2001. PubMed 11673367
  12. 12.American Diabetes Association Professional Practice Committee for Diabetes. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2026. Diabetes Care, 2026. doi:10.2337/dc26-S015
  13. 13.Stratton IM, Adler AI, Neil HA, et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. BMJ, 2000. doi:10.1136/bmj.321.7258.405
  14. 14.Diabetes Control and Complications Trial Research Group; Nathan DM, Genuth S, et al. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. New England Journal of Medicine, 1993. doi:10.1056/NEJM199309303291401
  15. 15.Battelino T, Danne T, Bergenstal RM, et al. Clinical Targets for Continuous Glucose Monitoring Data Interpretation: Recommendations From the International Consensus on Time in Range. Diabetes Care, 2019. doi:10.2337/dci19-0028

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