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A1C lookup

Use this A1C lookup tool to convert an A1C percentage into estimated average glucose (eAG) in both mg/dL and mmol/L. You can also use the chart below to compare A1C levels and review the common ranges for normal blood sugar, prediabetes, and diabetes.

A1C, also called HbA1c or glycated hemoglobin, is a blood test that reflects your average blood glucose over roughly the past 2 to 3 months. Many labs also report an estimated average glucose (eAG), which translates an A1C percentage into the same units used on a glucose meter or CGM.

You can also view an A1C conversion chart below.

What is A1C?

A1C is also known as glycated hemoglobin, hemoglobin A1C, or HbA1c. It measures the percentage of hemoglobin in your blood that has glucose attached to it. Because red blood cells live for about 3 months, the test gives a picture of your average blood sugar over time rather than your blood sugar at a single moment.

This makes A1C different from a fingerstick glucose reading or a fasting glucose test. A glucose meter tells you what your blood sugar is right now. An A1C test shows the longer-term trend.

What is a good A1C level?

For diagnosis, the standard A1C ranges are straightforward:

  • Below 5.7% is considered normal
  • 5.7% to 6.4% indicates prediabetes
  • 6.5% or above indicates diabetes

Within the 5.7% to 6.4% range, the risk of developing type 2 diabetes increases as the number rises. For people who already have diabetes, a “good” A1C target is more individualized and depends on age, medications, health history, and risk of low blood sugar.

How to convert A1C to average blood sugar

If you are more familiar with glucose readings in mg/dL or mmol/L, estimated average glucose can make an A1C result easier to understand.

To convert A1C to estimated average glucose in mg/dL, use this formula:

28.7 x A1C - 46.7 = eAG mg/dL

To convert A1C to estimated average glucose in mmol/L, use this formula:

(28.7 x A1C - 46.7) / 18 = eAG mmol/L

For example, an A1C of 6.0% converts to an estimated average glucose of about 126 mg/dL, while an A1C of 7.0% converts to about 154 mg/dL.

Common A1C values and what they mean

Here are a few common A1C levels and their estimated average glucose equivalents:

A1C Estimated average glucose (mg/dL) What it usually means
5.7% 117 Lower end of the prediabetes range
6.0% 126 Prediabetes range
6.4% 137 Upper end of the prediabetes range
6.5% 140 Threshold used for diabetes diagnosis
7.0% 154 Above the diabetes diagnostic threshold
8.0% 183 Higher average glucose over time

These examples are helpful for interpretation, but remember that A1C is still only one part of the picture. Two people with the same A1C can have very different day-to-day highs and lows.

How do you measure A1C?

A1C is usually measured with a blood test ordered by a doctor or performed through a lab. Unlike a fasting glucose test, fasting is usually not required for an A1C test.

There are also at-home A1C testing kits and digital A1C meters. These may be convenient, but lab testing remains the standard reference point when accuracy matters.

Why A1C and your glucose readings may not match

It is common for people to compare their A1C with meter readings or CGM averages and wonder why the numbers do not line up perfectly.

There are a few reasons for that:

  • A1C reflects a long-term average, not day-to-day swings
  • Fingerstick readings only capture specific moments
  • CGM averages may not match eAG exactly
  • Some medical conditions can affect the reliability of A1C

That is why A1C, fasting glucose, symptoms, and home readings are often interpreted together rather than in isolation.

A1C conversion chart

This chart converts A1C values from 1.0% to 20.0% into estimated average glucose (eAG) using the regression equation from the ADAG study, which is commonly used for lab-reported eAG.

  • eAG (mg/dL) = 28.7 x A1C - 46.7
  • eAG (mmol/L) = (28.7 x A1C - 46.7) / 18

Common A1C reference ranges:

  • Normal: below 5.7%
  • Prediabetes: 5.7% to 6.4%
  • Diabetes: 6.5% or above
A1C (%) Glucose (eAG) mg/dL Glucose (eAG) mmol/L
1.0-18-1
1.1-15-0.8
1.2-12-0.7
1.3-9-0.5
1.4-7-0.4
1.5-4-0.2
1.6-1-0.1
1.720.1
1.850.3
1.980.4
2.0110.6
2.1140.8
2.2160.9
2.3191.1
2.4221.2
2.5251.4
2.6281.6
2.7311.7
2.8341.9
2.9372.1
3.0392.2
3.1422.3
3.2452.5
3.3482.7
3.4512.8
3.5543
3.6573.2
3.7593.3
3.8623.4
3.9653.6
4.0683.8
4.1713.9
4.2744.1
4.3774.3
4.4804.4
4.5824.6
4.6854.7
4.7884.9
4.8915.1
4.9945.2
5.0975.4
5.11005.6
5.21035.7
5.31055.8
5.41086
5.51116.2
5.61146.3
5.71176.5
5.81206.7
5.91236.8
6.01267
6.11287.1
6.21317.3
6.31347.4
6.41377.6
6.51407.8
6.61437.9
6.71468.1
6.81488.2
6.91518.4
7.01548.6
7.11578.7
7.21608.9
7.31639.1
7.41669.2
7.51699.4
7.61719.5
7.71749.7
7.81779.8
7.918010
8.018310.2
8.118610.3
8.218910.5
8.319210.7
8.419410.8
8.519710.9
8.620011.1
8.720311.3
8.820611.4
8.920911.6
9.021211.8
9.121411.9
9.221712.1
9.322012.2
9.422312.4
9.522612.6
9.622912.7
9.723212.9
9.823513.1
9.923713.2
10.024013.3
10.124313.5
10.224613.7
10.324913.8
10.425214
10.525514.2
10.625814.3
10.726014.4
10.826314.6
10.926614.8
11.026914.9
11.127215.1
11.227515.3
11.327815.4
11.428015.6
11.528315.7
11.628615.9
11.728916.1
11.829216.2
11.929516.4
12.029816.6
12.130116.7
12.230316.8
12.330617
12.430917.2
12.531217.3
12.631517.5
12.731817.7
12.832117.8
12.932418
13.032618.1
13.132918.3
13.233218.4
13.333518.6
13.433818.8
13.534118.9
13.634419.1
13.734619.2
13.834919.4
13.935219.6
14.035519.7
14.135819.9
14.236120.1
14.336420.2
14.436720.4
14.536920.5
14.637220.7
14.737520.8
14.837821
14.938121.2
15.038421.3
15.138721.5
15.239021.7
15.339221.8
15.439521.9
15.539822.1
15.640122.3
15.740422.4
15.840722.6
15.941022.8
16.041322.9
16.141523.1
16.241823.2
16.342123.4
16.442423.6
16.542723.7
16.643023.9
16.743324.1
16.843524.2
16.943824.3
17.044124.5
17.144424.7
17.244724.8
17.345025
17.445325.2
17.545625.3
17.645825.4
17.746125.6
17.846425.8
17.946725.9
18.047026.1
18.147326.3
18.247626.4
18.347926.6
18.448126.7
18.548426.9
18.648727.1
18.749027.2
18.849327.4
18.949627.6
19.049927.7
19.150127.8
19.250428
19.350728.2
19.451028.3
19.551328.5
19.651628.7
19.751928.8
19.852229
19.952429.1
20.052729.3

Frequently asked questions

What does A1C measure?

A1C measures the percentage of hemoglobin in your blood that has glucose attached to it. It reflects your average blood sugar over about the past 3 months.

What is a normal A1C?

A normal A1C is below 5.7%.

What A1C level means prediabetes?

An A1C from 5.7% to 6.4% falls in the prediabetes range.

What A1C level means diabetes?

An A1C of 6.5% or above is in the diabetes range.

Is A1C the same as blood sugar?

No, A1C reflects a longer-term average, while a blood sugar reading shows your glucose at a specific moment.

Can A1C be inaccurate?

Yes, certain health conditions and situations can affect A1C results, especially anything that changes red blood cell lifespan or hemoglobin structure.

Relevant HSA expenses

If you have an HSA as part of your health insurance plan, you'll be pleased to find that blood glucose monitors and blood glucose testing supplies (such as test strips and lancets) are considered eligible expenses.

Sources

Disclaimer

This page is for educational purposes only and is not medical advice. A1C and eAG are tools that help describe average glucose, but they don't replace individualized guidance from a clinician. If you have diabetes, prediabetes, symptoms of high/low blood sugar, or results that don't seem to match your day-to-day readings, talk with a qualified healthcare professional. If you think you're having a medical emergency, please call 911 immediately.

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