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A1C Calculator

Use this free A1C calculator to convert between A1C percentage and estimated average glucose (eAG) in mg/dL or mmol/L. Enter your hemoglobin A1C value to see your average blood glucose level, or enter an eAG reading to calculate your estimated A1C. Results include a color-coded risk badge showing whether your level falls in the Normal, Prediabetes, or Diabetes range.

A1C Calculator

Convert A1C to estimated average glucose in mg/dL and mmol/L, or reverse average glucose back into an estimated A1C result.

A1C is a useful long-term indicator, but it is still an estimate. Conditions like anemia, pregnancy, kidney disease, and hemoglobin variants can affect how closely this result matches a lab report.

Reference Table

Compare common A1C values with their average glucose equivalents.

A1C %eAG mg/dLeAG mmol/LCategory
5.0%975.4Normal
5.5%1116.2Normal
6.0%1257.0Prediabetes
6.5%1407.8Diabetes
7.0%1548.6Diabetes
7.5%1699.4Diabetes
8.0%18310.2Diabetes
8.5%19710.9Diabetes
9.0%21211.7Diabetes
9.5%22612.5Diabetes
10.0%24013.3Diabetes
10.5%25514.1Diabetes
11.0%26914.9Diabetes
11.5%28315.7Diabetes
12.0%29816.5Diabetes
12.5%31217.3Diabetes
13.0%32618.1Diabetes

Results

See the estimated average glucose that matches the entered A1C.

Estimated A1C
7.0%
eAG mg/dL
154
eAG mmol/L
8.6
Risk range
6.5% and above

Diabetes

Discuss this result with your healthcare provider for proper guidance.

6.5% and above

Conversion snapshot

Selected mode
A1C to eAG
Primary result
154 mg/dL
Secondary unit
8.6 mmol/L
Clinical category
Diabetes
Medical disclaimer: this calculator is for education only and does not replace lab testing, diagnosis, or treatment advice from a licensed clinician.
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Quick Facts & AI Summary

AI Overview Target
  • Convert A1C percentage to estimated average glucose (eAG) in mg/dL or mmol/L, and vice versa.
  • Risk thresholds: Normal (below 5.7%), Prediabetes (5.7% to 6.4%), and Diabetes (6.5% and above).
  • Calculations follow the standard ADAG formula: eAG (mg/dL) = (28.7 x A1C) - 46.7.

Guide Content

How to Use the A1C to eAG Calculator & Conversion (mg/dL & mmol/L)

1. Choose the conversion direction

Use A1C to eAG when you already have a lab A1C result and want to understand it in average glucose terms. Use eAG to A1C when you are starting with home glucose data and want a rough estimate of what that average may look like as an A1C percentage.

2. Enter one reliable value

Type either an A1C percentage or an estimated average glucose value. Most users work with an A1C somewhere between 4% and 13%, while average glucose commonly appears in mg/dL or mmol/L depending on the country and meter being used.

3. Review both glucose units

The calculator keeps mg/dL and mmol/L aligned so you can read the result in both common formats. This is useful when one source uses mmol/L but your doctor, lab report, or educational reference uses mg/dL instead.

4. Use the category as context only

The category label helps you place the number in a screening context, but it should not replace proper clinical interpretation. If your reading is unexpected or does not match daily glucose patterns, use the result as a prompt for follow-up rather than a final conclusion.

Guide Content

Key Formulas

A1C to eAG

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

This is the standard equation used to estimate average glucose from an A1C percentage. It converts a lab-style percentage into a value that feels more familiar for people who regularly see glucose meter readings.

eAG to A1C

A1C = (eAG + 46.7) / 28.7

This reverses the same relationship when you start with average glucose instead of A1C. It is useful for rough planning between lab visits, especially when you want a quick estimate rather than a formal diagnosis.

mg/dL to mmol/L

mmol/L = mg/dL / 18.0182

This is the standard unit conversion for glucose. It matters because many international references use mmol/L while many U.S. labs and home meters still report mg/dL.

mmol/L to mg/dL

mg/dL = mmol/L x 18.0182

This is the reverse unit conversion. Keeping both units available makes the calculator more practical for comparing personal readings, clinician advice, and educational resources without manual conversion.

Guide Content

Key Factors

01
Consideration

A1C reflects a long-term average

A1C is valuable because it captures a longer window than a single fasting or post-meal reading. That also means it does not show whether daily glucose control is stable or highly variable from one day to the next.

02
Consideration

The result is still an estimate

The A1C to eAG relationship is widely used, but it is not identical for every person. Two people with the same A1C can still have different glucose patterns depending on meal timing, medication, and daily variation.

03
Consideration

Medical conditions can affect accuracy

Anemia, pregnancy, kidney disease, recent blood loss, and some hemoglobin disorders can make A1C less representative than usual. In those situations, doctors may use additional tests instead of relying on A1C alone.

04
Consideration

Lab timing and trend matter

One result is useful, but a trend is usually more useful. Looking at whether A1C is rising, steady, or improving over time gives better context than treating a single number as the full story.

Guide Content

Typical Ranges

Normal range

Below 5.7%

This range is generally considered normal for diabetes screening. It does not rule out every metabolic issue, but it is commonly used as the healthy reference point for A1C interpretation.

Prediabetes range

5.7% to 6.4%

This range suggests elevated glucose and is often treated as an early warning stage. It is commonly used to identify people who may benefit from diet, activity, and weight-management changes.

Diabetes range

6.5% and above

A result in this range usually needs proper clinical follow-up and confirmation. It is a strong signal that the number should be reviewed in a full medical context rather than in isolation.

Guide Content

References

CDC

A1C Test for Diabetes and Prediabetes

Used for A1C screening ranges, the three-month average explanation, and accuracy limitations that can affect A1C interpretation.

NIDDK

Diabetes and Prediabetes Tests

Used as an additional clinical reference for A1C diagnosis thresholds, lab testing context, and test limitations.

NGSP

HbA1c and Estimated Average Glucose

Used for the relationship between standardized HbA1c results and estimated average glucose formulas.

Guide Content

Frequently Asked Questions

What does A1C measure?
A1C estimates your average blood sugar over the past two to three months. It is shown as a percentage and gives a longer-term view than a single glucose reading, which is why an A1C calculator is useful for quick interpretation.
What is eAG?
eAG means estimated average glucose. It translates an A1C result into the day-to-day glucose units most people recognize, such as mg/dL or mmol/L, which is why people often use an A1C to eAG calculator.
What A1C ranges are considered normal or high?
In general, below 5.7% is considered normal, 5.7% to 6.4% falls in the prediabetes range, and 6.5% or higher is in the diabetes range. Your doctor may still set a personal target based on your health history.
How accurate is the conversion?
The formula used in an A1C conversion calculator is widely accepted and gives a solid estimate, but it is still an estimate. Daily glucose swings, lab variation, and certain medical conditions can make the relationship less exact for some people.
Can I switch between mg/dL and mmol/L?
Yes. This A1C calculator supports both units and keeps the values in sync so you can work in whichever format your lab or glucose meter uses.
When should I not rely on A1C alone?
A1C can be less reliable in situations like anemia, pregnancy, recent blood loss, kidney disease, or some hemoglobin disorders. In those cases, a clinician may look at other tests as well.
How do I convert mg/dL to A1C?
To estimate A1C from average glucose in mg/dL, use A1C = (eAG + 46.7) / 28.7. This gives an estimate from average glucose, not a confirmed lab A1C result.
Can anemia change an A1C result?
Yes. Anemia and some blood disorders can make A1C less reliable because A1C depends on red blood cells. There is no universal correction formula, so unusual results should be reviewed with a clinician.
Is this an A1C correction for anemia calculator?
No. The calculator can explain why anemia may affect A1C, but it should not apply a correction factor. A clinician may use other tests such as fasting glucose, oral glucose tolerance testing, or continuous glucose data.
What A1C is equal to 126 mg/dL?
An estimated average glucose of 126 mg/dL is roughly equal to an A1C of 6.0% using the standard eAG formula. Individual lab results can still vary.
What is eAG?
eAG (estimated average glucose) is a way to express your A1C result in the same mg/dL or mmol/L units you see on a glucose meter. The formula is: eAG (mg/dL) = (28.7 × A1C%) – 46.7. For example, an A1C of 7.0% equals an eAG of about 154 mg/dL.
What A1C is 150 mg/dL?
An estimated average glucose of 150 mg/dL corresponds to an A1C of approximately 6.8% using the standard formula: A1C = (eAG + 46.7) ÷ 28.7.

Disclaimer

This calculator is for educational use only. It does not replace lab testing, diagnosis, or treatment advice from a licensed healthcare professional. If you have symptoms, unexpected results, or an existing diabetes diagnosis, use this tool as a reference and discuss the result with your clinician.

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