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Health & Fitness

A1C to Average Glucose (eAG) Calculator

Converts an HbA1c percentage to estimated average glucose using the ADAG study regression (Nathan et al., 2008).

Your inputs

Change any value, everything updates instantly.

Allowed range 4–15 %.

Try an example

Estimated average glucose

140 mg/dL

This means your estimated average glucose works out to 140 mg/dL with the values you entered.

Estimated average glucose: 140 mg/dLIn mmol/L: 7.77 mmol/L
Estimated average glucoseIn mmol/L
140 mg/dL

What you are seeing

Each bar grows to show one result for your everyday situation.

The top bar is the main answer: 140 mg/dL.

Change hba1c (now 6.5) and every bar updates instantly.

In mmol/L

7.77 mmol/L

Worked out from your inputs using the formula below.

Result explanation: Estimated average glucose

140 mg/dL.

Real-life comparison: With hba1c 10% higher, it would be 159 mg/dL.

Low, normal or high? ADA reference: below 5.7% typical, 5.7–6.4% prediabetes range, 6.5%+ diabetes range. Not a diagnosis.

Graph and details

46.759.512150192384HbA1cmg/dL

How the answer changes with hba1c

How to read this chart: The line shows the main result across the allowed range. The dot marks your input.

What this calculator does

Converts an HbA1c percentage to estimated average glucose using the ADAG study regression (Nathan et al., 2008).

What your result means

This means your estimated average glucose works out to 140 mg/dL with the values you entered.

Real-life numbers vary, prices, habits and conditions change, so treat this as a practical guide.

Results are shown rounded; the full value is used internally.

The formulas

The same formula runs every time you change an input.

1. A1C to Average Glucose (eAG)

eAG (mg/dL) = 28.7 × A1C − 46.7; eAG (mmol/L) = eAG ÷ 18

Symbols

a1c
HbA1c (%)

Why this formula works

This is the standard everyday arithmetic for this situation, using the values you enter.

Unit check

Inputs are converted to consistent units before calculating ✓

Worked example

  1. Substitute your values: HbA1c = 6.5
  2. Apply the formula: eAG (mg/dL) = 28.7 × A1C − 46.7; eAG (mmol/L) = eAG ÷ 18 = 139.85

Common mistakes

  • Entering a value in the wrong unit (for example minutes instead of hours).
  • Using an outdated price or rate.
  • Forgetting extra costs or time that apply in your case.

Working for your numbers

  1. Substitute your values: HbA1c = 6.5
  2. Apply the formula: eAG (mg/dL) = 28.7 × A1C − 46.7; eAG (mmol/L) = eAG ÷ 18 = 139.85

This means your estimated average glucose works out to 140 mg/dL with the values you entered.

Frequently asked questions

What does this a1c to average glucose (eag) calculator calculate?

Converts an HbA1c percentage to estimated average glucose using the ADAG study regression (Nathan et al., 2008).

How accurate is the result?

The calculation follows the stated formula exactly. Your result is an estimate and depends on the accuracy of the values you enter.

Can I use different units or currencies?

Yes. Use the controls beside the calculator inputs. Conversions preserve the underlying value used by the formula.

Symbols and assumptions

a1c
HbA1c (%)
  • Values entered are realistic for your situation.
  • Rates and prices stay constant over the period calculated.
  • Displayed values are rounded; internal values are not.

Sources and review

Reviewed 2026-09-25 · Next review 2027-09-25

Time and Frequency DivisionNISTHandbook 44 — specifications for weighing and measuring devicesNIST

Important limitation. Practical estimate for everyday planning. Real outcomes depend on prices, conditions and personal circumstances, check important figures before relying on them.

Quick reference

A1C to Average Glucose (eAG) Calculator: results for common inputs, worked out with the formula on this page.
ScenarioHbA1c (%)Estimated average glucose
Worked example6.5139.85 mg/dL
Half the amounts468.1 mg/dL
Double the amounts13326.4 mg/dL

Need the full picture? Get the detailed PDF report with charts, tables, formulas and working steps.

Reviewed 2026-10-18 · Next review 2027-04-18

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