Skip to content
A1c Formula
GaryTardiff posted:
I have seen several times on here where someone will say, "If you have an A1c of x.x that means that your average BG is xxx. What is the formula used to determine this?
DavidHueben responded:

You can go to the following web site and find an online calculator to convert the A1C to average plasma glucose:

mrscora01 responded:
There are two formulas that I have seen used.
The usual formula to estimate the relationship between A1c and mean plasma glucose was derived from the DCCT study.

That formula is:

Mean Blood Glucose = (A1c * 35.6) - 77.3

There is another, less cited formula that works better, at least for me. It is called "The Nathan Formula" it is:

Mean Plasma Glucose = (A1c * 33.3) -86

This formula yields a mean plasma glucose which comes much closer to what my meter's 30 day average has looked like.

There are also a number of different online calculators that you can find by googling.

GaryTardiff responded:
Well, I'd still love to know the formula used I found a great converter on the ADA site. Check it out
GaryTardiff replied to GaryTardiff's response:
Thanks for the info guys!!

Helpful Tips

Different glucose meters
I used a accu check nano for 2 years and recently had to switch to a one touch verio due to insurance plan. The readings went up by 33%. ... More
Was this Helpful?
9 of 9 found this helpful

Expert Blog

Conquering Diabetes - Michael Dansinger, MD

Dr. Michael Dansinger provides thoughtful tips for those with type 2 diabetes or pre-diabetes who want to reclaim their health...Read More

Related Drug Reviews

  • Drug Name User Reviews

Report Problems With Your Medications to the FDA

FDAYou are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.