HbA1c Converter · ADAG · ADA 2025

HbA1c ↔ Average Glucose Converter

Converts HbA1c (%) to estimated average glucose (eAG, mg/dL and mmol/L) and IFCC units (mmol/mol), mapped to ADA 2025 diagnostic cut-offs and targets.

What this tool does

Convert HbA1c (%) to estimated average glucose (eAG) and IFCC units.

What you need

Your most recent HbA1c value.

What the result means

Converted values and context; anaemia, transfusion and advanced CKD can make HbA1c under- or over-estimate — discuss with your doctor.

Enter the values above

Kidney patients: in CKD stage 4–5, dialysis, anaemia, ESA therapy or transfusion, altered red-cell lifespan makes HbA1c under- or over-estimate true glucose; glucose monitoring or CGM (time in range >70%) is preferred.

Privacy: all calculations run on your device; no values are sent to a server or third party. Log-type tools store data only in your browser (localStorage); clearing browsing data removes it.

This is not a diagnosis. It maps the numbers you entered onto published guideline categories; a real assessment needs a clinician, your history, repeat testing and other investigations.

Scope and limitations

  • The ADAG study (507 participants) conversion has larger error across ethnic groups and in anaemia or haemoglobin variants (e.g. thalassaemia).
  • HbA1c is unreliable in pregnancy, recent major blood loss or transfusion, splenectomy and some HIV treatments.
  • Targets are individualised; this tool shows general guideline principles only and does not replace your clinician's judgement.
  • HbA1c cannot show hypoglycaemia frequency; people with frequent lows need treatment changes even with an "on-target" HbA1c.

Formula & cut-off sources

  1. Nathan DM, et al. Translating the A1C assay into estimated average glucose values (ADAG). Diabetes Care 2008;31:1473–1478
  2. Hoelzel W, et al. IFCC reference system for measurement of HbA1c; NGSP–IFCC master equation. Clin Chem 2004;50:166–174
  3. American Diabetes Association. Standards of Care in Diabetes—2025 (Sec. 6 Glycemic Goals). Diabetes Care 2025;48(Suppl 1)
  4. KDIGO 2022 Clinical Practice Guideline for Diabetes Management in CKD. Kidney Int 2022;102(5S):S1–S127

To discuss with your doctor

  1. What is my HbA1c target, and why?
  2. Is my HbA1c reliable given my kidney function/anaemia? Should I use CGM?
  3. Do I have records of hypoglycaemia?
  4. Do my glucose medicines need adjusting as kidney function falls?

Next step

After this result, people usually continue with: