Home> Calculators > Glycosylated Hemoglobin (HbA1c).
Glycosylated hemoglobin (HbA1c) is formed by the attachment of glucose to hemoglobin (the oxygen carrying protein found in red blood cells). The percentage of glycosylated hemoglobin in the blood reflects the average blood sugar levels over the preceding 2 months.

The calculator below can be used to estimate the average blood sugar level based on the measured percentage of glycosylated hemoglobin (HbA1c).

Enter Glycosylated Hemoglobin (HbA1c) =  

Average plasma blood glucose = mg/dl      mmol/L

Average whole blood glucose = mg/dl     mmol/L


A HbA1c value > 6.5% is the threshold for diagnosis of diabetes

The Sweet Success Program of California recommends that individuals with an A1C of 5.7-6.4% (pre diabetes-glucose intolerance) should be informed of their increased risk for diabetes , and should receive early diet education and exercise modifications similar to patients with gestational diabetes.


  • Average Plasma Blood Glucose (mg/dl) = (HbA1c * 35.6) - 77.3
  • Average Plasma Blood Glucose (mmol/L) = (HbA1c * 1.98) - 4.29
  • Average whole blood glucose = Plasma Blood Glucose / 1.12

1. Rohlfing CL et al.Defining the Relationship Between Plasma Glucose and HbA1c, Analysis of glucose profiles and HbA1c in the Diabetes Control and Complications Trial," Diabetes Care 25:275-278, 2002.PUBMED
2. Guidelines for Diagnosis of Hyperglycemia in Pregnancy 2011http://www.cdph.ca.gov/programs/cdapp/Documents/MO-CDAPP-HyperglycemiaAlgorithm-7-18-11.pdf Accessed 6/20/2012


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