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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.

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How to Use A1C Calculator

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

Frequently Asked Questions

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%.

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

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

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

Using the A1C Calculator is simple: visit the tool page, enter your data or input into the provided fields, and get instant results. No downloads, installations, or sign-ups are required. The tool runs directly in your web browser for maximum convenience.

Yes, the A1C Calculator is fully responsive and works perfectly on smartphones, tablets, and desktop computers. Simply open NexTool in your mobile browser and navigate to the tool — no app download required.

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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.

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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%683.8Normal
4.5%824.6Normal
5.0%975.4Normal
5.5%1116.2Normal
5.7%1176.5Prediabetes
6.0%1267.0Prediabetes
6.5%You1407.8Diabetes
7.0%1548.6Diabetes
7.5%1699.4Diabetes
8.0%18310.2Diabetes
8.5%19710.9Diabetes
9.0%21211.8Diabetes
9.5%22612.6Diabetes
10.0%24013.4Diabetes
10.5%25514.2Diabetes
11.0%26914.9Diabetes
11.5%28315.7Diabetes
12.0%29816.5Diabetes

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.