HbA1c converter

The UK reports HbA1c in mmol/mol; older leaflets and US sites use per cent. Convert between the two.

Your details

6.0% is

42 mmol/mol

42 to 47: the prediabetes range

In mmol/mol (UK labs)42.1
In per cent (older and US style)6.00
Prediabetes range42 to 47 mmol/mol (6.0 to 6.4%)
Diabetes range48 mmol/mol (6.5%) or more
The sum (IFCC and NGSP master equation)(6.00 − 2.152) ÷ 0.09148 = 42.1 mmol/mol
Estimated average glucose (ADAG)about 7.0 mmol/L

Diabetes UK calls 42 to 47 prediabetes. It means a higher chance of type 2 diabetes, and it is often reversible: small changes in food, activity and weight can bring it back under 42. Diabetes UK says your GP should offer you a type 2 prevention course or advice.

If you feel very unwell with high sugar readings, call 111 the same day, or 999 in an emergency. 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.

IFCC to per cent

Going from mmol/mol to a percentage

UK labs report HbA1c in IFCC units, mmol/mol. To get the older percentage (NGSP/DCCT), multiply by 0.09148 and add 2.152: 48 mmol/mol is 0.09148 × 48 + 2.152 = 6.5%. Pick mmol/mol to per cent above, and add an earlier result to see the change in both units.

The working

6.0% in UK units

The master equation is per cent = 0.09148 x mmol/mol + 2.152. Turned round: (6.0 − 2.152) ÷ 0.09148 = 42 mmol/mol. That is the bottom of the 42 to 47 range Diabetes UK calls prediabetes.

The ranges

Where results sit

mmol/mol	Per cent	What Diabetes UK calls it
under 42	under 6.0%	normal range
42 to 47	6.0 to 6.4%	prediabetes
48 or more	6.5% or more	diabetes range
48 or below	6.5% or below	ideal for many people with diabetes (your team may set another)

Quick table

Common values

Per cent	mmol/mol
5.5%	37
6.0%	42
6.5%	48
7.0%	53
7.5%	58
8.0%	64
9.0%	75

Read with care

What this cannot tell you

A unit converter with the UK ranges, nothing more.

Diagnose diabetesThat is your GP's call, with your other results.
Show daily highs and lowsHbA1c is a 2 to 3 month average.
Work for everyoneSome blood conditions and pregnancy make HbA1c less reliable.

Questions

Common questions

How do I convert IFCC HbA1c to a percentage?

Multiply the mmol/mol figure by 0.09148 and add 2.152. 42 mmol/mol is 6.0%, 48 is 6.5% and 53 is 7.0%.

How do I convert HbA1c percent to mmol/mol?

Subtract 2.152, then divide by 0.09148. 7% becomes 53 mmol/mol.

What HbA1c is prediabetes?

42 to 47 mmol/mol, which is 6.0 to 6.4%.

What HbA1c means diabetes?

48 mmol/mol (6.5%) or more is the diabetes range. Your GP confirms a diagnosis, not a converter.

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.