HbA1c Calculator — Convert HbA1c to Average Blood Sugar

This page is reference information, not medical advice.

Nothing here can diagnose you, and nothing here is a treatment plan. Blood glucose results are interpreted by a doctor alongside your history, your symptoms and a repeat test — a single number on a screen is not a diagnosis. If any reading concerns you, or if you feel unwell, see a doctor rather than a website.

The equation

eAG (mg/dL) = 28.7 × HbA1c(%) − 46.7
eAG (mmol/L) = eAG (mg/dL) ÷ 18.016
HbA1c (mmol/mol) = (HbA1c(%) − 2.15) × 10.929

The first line is the linear regression from the A1c-Derived Average Glucose study, published in Diabetes Care in 2008. It came from 507 people across ten international centres, each of whom wore continuous glucose monitors and took frequent finger-prick readings over three months, and it explained about 84% of the variation between HbA1c and measured average glucose. It is the equation the American Diabetes Association uses.

The third line is the NGSP master equation, which converts between the percentage most Indian labs report and the mmol/mol unit used internationally.

Source: Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ, for the A1c-Derived Average Glucose (ADAG) Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31(8):1473–1478. Link
Source: National Glycohemoglobin Standardization Program (NGSP) — HbA1c and estimated average glucose (eAG). Link

The full conversion table

Every HbA1c from 4.0% to 14.0% in steps of 0.1. This table is the calculator — the box above only saves you finding your row.

HbA1c converted to estimated average glucose with the ADAG regression, eAG (mg/dL) = 28.7 × A1C − 46.7. The mmol/mol column is the IFCC unit, from the NGSP master equation. The final column reads the A1C against the ADA diagnostic bands.
HbA1c (%)	mmol/mol	eAG (mg/dL)	eAG (mmol/L)	Where it sits
4.0%	20	68	3.8	Below the prediabetes range
4.1%	21	71	3.9	Below the prediabetes range
4.2%	22	74	4.1	Below the prediabetes range
4.3%	23	77	4.3	Below the prediabetes range
4.4%	25	80	4.4	Below the prediabetes range
4.5%	26	82	4.6	Below the prediabetes range
4.6%	27	85	4.7	Below the prediabetes range
4.7%	28	88	4.9	Below the prediabetes range
4.8%	29	91	5.1	Below the prediabetes range
4.9%	30	94	5.2	Below the prediabetes range
5.0%	31	97	5.4	Below the prediabetes range
5.1%	32	100	5.5	Below the prediabetes range
5.2%	33	103	5.7	Below the prediabetes range
5.3%	34	105	5.9	Below the prediabetes range
5.4%	36	108	6.0	Below the prediabetes range
5.5%	37	111	6.2	Below the prediabetes range
5.6%	38	114	6.3	Below the prediabetes range
5.7%	39	117	6.5	In the prediabetes range
5.8%	40	120	6.6	In the prediabetes range
5.9%	41	123	6.8	In the prediabetes range
6.0%	42	126	7.0	In the prediabetes range
6.1%	43	128	7.1	In the prediabetes range
6.2%	44	131	7.3	In the prediabetes range
6.3%	45	134	7.4	In the prediabetes range
6.4%	46	137	7.6	In the prediabetes range
6.5%	48	140	7.8	In the diabetes range
6.6%	49	143	7.9	In the diabetes range
6.7%	50	146	8.1	In the diabetes range
6.8%	51	148	8.2	In the diabetes range
6.9%	52	151	8.4	In the diabetes range
7.0%	53	154	8.6	In the diabetes range
7.1%	54	157	8.7	In the diabetes range
7.2%	55	160	8.9	In the diabetes range
7.3%	56	163	9.0	In the diabetes range
7.4%	57	166	9.2	In the diabetes range
7.5%	58	169	9.4	In the diabetes range
7.6%	60	171	9.5	In the diabetes range
7.7%	61	174	9.7	In the diabetes range
7.8%	62	177	9.8	In the diabetes range
7.9%	63	180	10.0	In the diabetes range
8.0%	64	183	10.2	In the diabetes range
8.1%	65	186	10.3	In the diabetes range
8.2%	66	189	10.5	In the diabetes range
8.3%	67	192	10.6	In the diabetes range
8.4%	68	194	10.8	In the diabetes range
8.5%	69	197	10.9	In the diabetes range
8.6%	70	200	11.1	In the diabetes range
8.7%	72	203	11.3	In the diabetes range
8.8%	73	206	11.4	In the diabetes range
8.9%	74	209	11.6	In the diabetes range
9.0%	75	212	11.7	In the diabetes range
9.1%	76	214	11.9	In the diabetes range
9.2%	77	217	12.1	In the diabetes range
9.3%	78	220	12.2	In the diabetes range
9.4%	79	223	12.4	In the diabetes range
9.5%	80	226	12.5	In the diabetes range
9.6%	81	229	12.7	In the diabetes range
9.7%	83	232	12.9	In the diabetes range
9.8%	84	235	13.0	In the diabetes range
9.9%	85	237	13.2	In the diabetes range
10.0%	86	240	13.3	In the diabetes range
10.1%	87	243	13.5	In the diabetes range
10.2%	88	246	13.7	In the diabetes range
10.3%	89	249	13.8	In the diabetes range
10.4%	90	252	14.0	In the diabetes range
10.5%	91	255	14.1	In the diabetes range
10.6%	92	258	14.3	In the diabetes range
10.7%	93	260	14.5	In the diabetes range
10.8%	95	263	14.6	In the diabetes range
10.9%	96	266	14.8	In the diabetes range
11.0%	97	269	14.9	In the diabetes range
11.1%	98	272	15.1	In the diabetes range
11.2%	99	275	15.2	In the diabetes range
11.3%	100	278	15.4	In the diabetes range
11.4%	101	280	15.6	In the diabetes range
11.5%	102	283	15.7	In the diabetes range
11.6%	103	286	15.9	In the diabetes range
11.7%	104	289	16.0	In the diabetes range
11.8%	105	292	16.2	In the diabetes range
11.9%	107	295	16.4	In the diabetes range
12.0%	108	298	16.5	In the diabetes range
12.1%	109	301	16.7	In the diabetes range
12.2%	110	303	16.8	In the diabetes range
12.3%	111	306	17.0	In the diabetes range
12.4%	112	309	17.2	In the diabetes range
12.5%	113	312	17.3	In the diabetes range
12.6%	114	315	17.5	In the diabetes range
12.7%	115	318	17.6	In the diabetes range
12.8%	116	321	17.8	In the diabetes range
12.9%	117	324	18.0	In the diabetes range
13.0%	119	326	18.1	In the diabetes range
13.1%	120	329	18.3	In the diabetes range
13.2%	121	332	18.4	In the diabetes range
13.3%	122	335	18.6	In the diabetes range
13.4%	123	338	18.8	In the diabetes range
13.5%	124	341	18.9	In the diabetes range
13.6%	125	344	19.1	In the diabetes range
13.7%	126	346	19.2	In the diabetes range
13.8%	127	349	19.4	In the diabetes range
13.9%	128	352	19.6	In the diabetes range
14.0%	130	355	19.7	In the diabetes range

Estimated average glucose is an average across roughly the previous three months. It is not a prediction of your reading tomorrow morning, and two people with the same HbA1c can have very different day-to-day swings.

What the number is, and is not

Estimated average glucose is an average over roughly the previous two to three months, weighted towards the more recent weeks. It is not a prediction of tomorrow morning's reading, and it cannot distinguish a person whose glucose sits steadily near the average from one swinging widely either side of it.

There are also well-documented situations in which HbA1c itself is not a reliable measure of average glucose — anaemia, some inherited haemoglobin variants, recent transfusion, advanced kidney disease and pregnancy among them. Several of those are common in India. The detail is here.

This converter does not interpret your result and does not set a target. Whether a particular HbA1c calls for anything, and what, is a clinical decision made by a doctor who knows your history. If your result concerns you, take it to one.

PeakForm is a training and accountability programme. It is not a treatment for diabetes or prediabetes, it is not a substitute for your doctor's advice, and nothing on this site should be acted on before speaking to one.

Common questions

How do you convert HbA1c to average blood sugar?

With the ADAG regression published in Diabetes Care in 2008: estimated average glucose in mg/dL = 28.7 × HbA1c − 46.7. For mmol/L, divide that result by 18.016. An HbA1c of 7.0% gives 154 mg/dL, or 8.6 mmol/L.

What is a normal HbA1c?

Below 5.7% on the ADA criteria. 5.7% to 6.4% is the prediabetes range, and 6.5% or above is in the diabetes range. WHO also uses 6.5% as its diagnostic cut-off and states that a value below it does not rule diabetes out.

What is HbA1c in mmol/mol?

The IFCC unit. The NGSP master equation converts it: mmol/mol = (percentage − 2.15) × 10.929. So 6.5% is 48 mmol/mol and 7.0% is 53 mmol/mol.

Is estimated average glucose the same as my glucometer average?

Not exactly. eAG is a statistical translation of HbA1c derived from a study of 507 people, and the regression explained about 84% of the variation. Your own measured average can sit either side of it, and two people with the same HbA1c can have very different day-to-day swings.

Conversion from the ADAG study (Nathan et al., Diabetes Care 2008) and the NGSP master equation. Diagnostic bands from the ADA Standards of Care. General information only — NOT medical advice, and never a diagnosis. Only a doctor can interpret your results and diagnose or treat diabetes. If a reading concerns you, see a doctor rather than a website. Every threshold, equation and glycemic index value used on this site is listed with its publication on the data & method page.

HbA1c to average glucose

The equation

The full conversion table

What the number is, and is not

Common questions

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