A1C Calculator

Convert between A1C and average blood sugar levels with color-coded diabetes risk ranges, reference charts, and bidirectional conversion. Free, fast, and private — runs entirely in your browser.

Convert From

A1C Percentage (%)

3%14%

Estimated Average Glucose (eAG)

140 mg/dL

(7.8 mmol/L)

Diabetes

Your blood sugar is in the diabetes range. Consult your healthcare provider for management options.

3%Normal <5.7%Pre 5.7-6.4%Diabetes ≥6.5%14%

A1C

6.5%

eAG (mg/dL)

140

eAG (mmol/L)

7.8

3-Month Blood Sugar Trend Interpretation

Your A1C of 6.5% reflects your average blood sugar over the past 2-3 months. This means your blood sugar has been averaging around 140 mg/dL (7.8 mmol/L) during this period.

What This Means

A1C measures glycated hemoglobin, reflecting average glucose over red blood cell lifespan (~120 days)
More recent weeks contribute more heavily to the A1C value than earlier weeks
Individual readings can vary significantly from this average throughout the day

Factors That Can Affect Accuracy

Anemia or hemoglobin variants may skew results
Recent blood transfusions can affect readings
Kidney disease and liver disease may cause inaccuracies
Pregnancy can affect A1C interpretation

A1C Target Ranges

Most adults with diabetes

Target: Below 7.0%

Within Target

Older adults / complex conditions

Target: Below 8.0%

Within Target

Pregnancy (GDM)

Target: Below 6.0%

+0.5% above

Non-diabetic (healthy)

Target: Below 5.7%

+0.8% above

A1C to Blood Sugar Reference Table

A1C (%)	eAG (mg/dL)	eAG (mmol/L)	Classification
4.0%	68	3.8	Normal
4.5%	82	4.6	Normal
5.0%	97	5.4	Normal
5.5%	111	6.2	Normal
5.7%	117	6.5	Prediabetes
6.0%	126	7.0	Prediabetes
6.5%You	140	7.8	Diabetes
7.0%	154	8.6	Diabetes
7.5%	169	9.4	Diabetes
8.0%	183	10.2	Diabetes
8.5%	197	10.9	Diabetes
9.0%	212	11.8	Diabetes
9.5%	226	12.6	Diabetes
10.0%	240	13.4	Diabetes
10.5%	255	14.2	Diabetes
11.0%	269	14.9	Diabetes
11.5%	283	15.7	Diabetes
12.0%	298	16.5	Diabetes

Conversion Formula

A1C to Blood Sugar

eAG (mg/dL) = 28.7 x A1C - 46.7

Example: 28.7 x 6.5 - 46.7 = 139.8 mg/dL

Blood Sugar to A1C

A1C = (eAG + 46.7) / 28.7

Example: (140 + 46.7) / 28.7 = 6.5%

Based on the ADAG (A1C-Derived Average Glucose) study published in Diabetes Care. This formula is endorsed by the American Diabetes Association and used internationally.

mg/dL and mmol/L Conversion

mg/dL to mmol/L

Divide by 18.0182

mmol/L to mg/dL

Multiply by 18.0182

mg/dL is used primarily in the US. mmol/L is the international standard used in most other countries.

Medical Disclaimer

This calculator provides estimates based on the ADAG study formula. Individual results may vary. The eAG is an approximation and does not replace regular blood glucose monitoring. Always consult your healthcare provider for medical advice, diagnosis, and treatment decisions. Do not make changes to your medication or treatment based solely on this calculator.

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How to Use A1C Calculator

1Enter your A1C percentage or average blood sugar.
2View the converted value instantly.
3Check the color-coded risk range (normal, prediabetes, diabetes).
4Reference the A1C-to-glucose conversion table.

Frequently Asked Questions

What is A1C?▾

A1C (HbA1c) measures your average blood sugar over the past 2-3 months. It's used to diagnose and monitor diabetes. Normal is below 5.7%.

How is A1C converted to blood sugar?▾

Using the formula: eAG (mg/dL) = 28.7 × A1C − 46.7. This gives the estimated average glucose corresponding to your A1C level.

Is this calculator free?▾

Yes, completely free with no sign-up required. All calculations run in your browser.

Should I use this instead of seeing a doctor?▾

No, this is for educational purposes only. Always consult your healthcare provider for diabetes diagnosis and management.

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About A1C Calculator

Convert between A1C and average blood sugar levels with color-coded diabetes risk ranges, reference charts, and bidirectional conversion. Free, fast, and private — runs entirely in your browser.

NexTool's A1C Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.