HbA1c to Average Blood Sugar Conversion: Complete Chart and Formula

Published 18 August 2026

An HbA1c to average blood sugar conversion translates your three-month glycated haemoglobin percentage into an estimated average glucose (eAG) level [ADA, 2008]. This calculation uses a standardised formula to show glucose concentrations in mg/dL or mmol/L [ADA, 2008].

How do you convert HbA1c to average blood sugar?

Your laboratory report shows your HbA1c result as a percentage [ADA, 2008]. An estimated average glucose (eAG) level translates this percentage into daily blood sugar terms [ADA, 2008].

The American Diabetes Association established this standard conversion formula [ADA, 2008]:

eAG (mg/dL) = 28.7 × HbA1c% − 46.7

To calculate average glucose in millimoles per litre, use this formula [ADA, 2008]:

eAG (mmol/L) = 1.59 × HbA1c% − 2.59

For example, an HbA1c of 6.5% converts to an eAG of 140 mg/dL or 7.8 mmol/L [ADA, 2008].

See what your own HbA1c means — upload your report free here

What does the HbA1c to average blood sugar conversion chart show?

The table below shows estimated average glucose values for every HbA1c level from 5.0% to 13.0% in 0.5% steps [ADA, 2008]. Both mg/dL and mmol/L are shown so you can read your result in whichever unit your report uses.

HbA1c (%)	eAG (mg/dL)	eAG (mmol/L)
5.0%	97	5.4
5.5%	111	6.2
6.0%	125	6.9
6.5%	140	7.8
7.0%	154	8.5
7.5%	169	9.4
8.0%	183	10.2
8.5%	197	10.9
9.0%	212	11.8
9.5%	226	12.5
10.0%	240	13.3
10.5%	255	14.2
11.0%	269	14.9
11.5%	283	15.7
12.0%	298	16.5
12.5%	312	17.3
13.0%	326	18.1

Formula: eAG (mg/dL) = 28.7 × HbA1c% − 46.7 [ADA, 2008]. To convert mg/dL to mmol/L, divide by 18.018.

What does an HbA1c result in the prediabetes range mean?

An HbA1c between 5.7% and 6.4% indicates prediabetes under ADA guidelines [ADA, 2024]. RSSDI uses the same threshold for Indian adults [RSSDI, 2022].

If your result is 5.7%, 5.8%, or 5.9%, your estimated average sugar sits between 117 mg/dL and 123 mg/dL [ADA, 2008]. These values fall at the lower end of the prediabetes range.

If your result is 6.0%, 6.1%, 6.2%, 6.3%, or 6.4%, your average sugar ranges from 125 mg/dL to 137 mg/dL [ADA, 2008]. These values sit in the upper part of the prediabetes range. An HbA1c in this band is worth discussing with your doctor.

How do ADA and RSSDI classify HbA1c thresholds?

Both the American Diabetes Association and the Research Society for the Study of Diabetes in India publish aligned classification thresholds [ADA, 2024; RSSDI, 2022].

Category	HbA1c range	ADA source	RSSDI source
Normal	Below 5.7%	ADA, 2024	RSSDI, 2022
Prediabetes	5.7% to 6.4%	ADA, 2024	RSSDI, 2022
Diabetes threshold	6.5% and above	ADA, 2024	RSSDI, 2022

An HbA1c of 6.9% equals an estimated average glucose of 151 mg/dL [ADA, 2008]. This falls above the diabetes threshold in both guidelines [ADA, 2024; RSSDI, 2022]. A result in this range is worth discussing with your doctor alongside your fasting and post-meal glucose readings.

What is the difference between HbA1c and fasting blood sugar?

Fasting blood sugar measures glucose at a single moment in time. HbA1c reflects average glucose across the preceding two to three months [ADA, 2024; ICMR, 2023]. Both tests give different but complementary information. Your doctor may use both together to get a fuller picture.

Frequently asked questions

What does an HbA1c of 6.5% convert to in average blood sugar?

An HbA1c of 6.5% equals an estimated average glucose of 140 mg/dL or 7.8 mmol/L [ADA, 2008]. This sits at the diabetes threshold under ADA and RSSDI guidelines [ADA, 2024; RSSDI, 2022].

What does an HbA1c of 5.7% mean on a report?

An HbA1c of 5.7% marks the lower boundary of the prediabetes range [ADA, 2024]. It corresponds to an estimated average glucose of 117 mg/dL [ADA, 2008]. It is worth discussing with your doctor at your next visit.

What does an HbA1c of 6.9% mean?

An HbA1c of 6.9% reflects an estimated average glucose of 151 mg/dL [ADA, 2008]. This value sits above the diabetes threshold under both ADA [ADA, 2024] and RSSDI guidelines [RSSDI, 2022]. Discuss this result with your doctor.

How often does HbA1c reflect average glucose changes?

HbA1c reflects average blood glucose levels over the preceding two to three months [ADA, 2024; ICMR, 2023]. A test done today reflects how your blood sugar has behaved since roughly the same time last quarter.

Can fasting blood sugar replace an HbA1c test?

No — they measure different things. Fasting blood sugar captures one moment; HbA1c captures the average over 90 days [ADA, 2024; ICMR, 2023]. Doctors often use both together for a complete picture.

Why do Indian labs sometimes use different HbA1c thresholds?

Most Indian labs follow RSSDI or ADA thresholds, which are aligned [RSSDI, 2022; ADA, 2024]. Always compare your result against the range printed on your own report — lab methods and population calibrations vary [CLSI, C28-A3].

Sources

American Diabetes Association (ADA). Translating the A1C Assay Into Estimated Average Glucose Values, 2008.
American Diabetes Association (ADA). Standards of Care in Diabetes, 2024.
Indian Council of Medical Research (ICMR). Guidelines for Management of Type 2 Diabetes, 2023.
Research Society for the Study of Diabetes in India (RSSDI). Clinical Practice Recommendations for Management of Type 2 Diabetes, 2022.
Clinical and Laboratory Standards Institute (CLSI). Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory — Third Edition (C28-A3).