Average glucose from HbA1c

Convert your HbA1c in mmol/mol into an average blood sugar in mmol/L, the units your meter uses, as a rough three month average.

Your details

HbA1c 53 mmol/mol (7.0%) works out at about

8.6 mmol/L

estimated average glucose

In mg/dL154
The sum (ADAG, Nathan 2008)28.7 x 7.0 minus 46.7 = 154 mg/dL, then ÷ 18
Where 53 sits (no diabetes diagnosed)48 or more: in the type 2 diabetes range, which needs a GP to confirm

This is an average over 2 to 3 months, so it hides highs and lows. Two people with the same HbA1c can have quite different finger prick or sensor averages, and some blood conditions make HbA1c less reliable. If your meter or sensor disagrees with this, believe the meter for day to day decisions and tell your team.

If a result worries you, ask your GP surgery or practice nurse to talk it through. Call 111 if you feel unwell and are not sure what to do.

The working

An HbA1c of 7.0%

The ADAG study (Nathan 2008) found average glucose in mg/dL = 28.7 x HbA1c% − 46.7. So 28.7 x 7.0 − 46.7 = 154 mg/dL, and 154 ÷ 18 = 8.6 mmol/L. If your result is in mmol/mol, it is turned into per cent first with the master equation.

Quick table

Common values

HbA1c	mmol/mol	Average glucose
6.0%	42	7.0 mmol/L
6.5%	48	7.8 mmol/L
7.0%	53	8.6 mmol/L
8.0%	64	10.2 mmol/L
9.0%	75	11.8 mmol/L

When they disagree

Meter and HbA1c out of step

An average hides the shape of your days: two people with an HbA1c of 7% can have very different highs and lows. If your sensor average and this estimate are far apart, mention it to your team; there are known reasons, and they can check.

What the number means

Ranges and targets in the UK

Situation	HbA1c (mmol/mol)
Usual range	below 42
Prediabetes	42 to 47
Type 2 diabetes range (a GP confirms)	48 or more
Type 2 target, diet or one medicine without hypos (NICE NG28)	48
Type 2 target with a medicine that can cause hypos (NICE NG28)	53
Type 1 aim (NICE NG17)	48 or lower

7.0% is 53 mmol/mol and an average glucose of about 8.6 mmol/L. Add your last result to see the change: from 58 to 53 is a fall of 5 mmol/mol, an average about 0.7 mmol/L lower. Targets are agreed with your diabetes team and can be different for you.

Read with care

What this cannot tell you

Show highs and lowsAn average cannot.
Replace a sensor reportTime in range is a better daily picture.
Fit everybodyThe formula is a best fit across many people, not you exactly.

Questions

Common questions

What average glucose is HbA1c 48?

About 7.8 mmol/L (141 mg/dL).

Why does my meter average not match my HbA1c?

Meters only see the moments you test, and HbA1c can read differently in some people. Your team can help make sense of it.

How do I convert mg/dL to mmol/L?

Divide by 18. So 180 mg/dL is 10 mmol/L.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Talk your results through

If a result worries you, book a chat with your GP or practice nurse, or ask a pharmacist. Call NHS 111 if you feel unwell and are not sure what to do, and 999 in an emergency.