MHMW

Glucose to A1C calculator: average blood sugar to A1C

A1C corresponding to an average glucose of 154 mg/dLworked example

7%

In the other glucose unit
8.5 mmol/L
In IFCC units
53 mmol/mol
ADA range
the range the ADA uses to diagnose diabetes

An average glucose of 154 mg/dL works out to an A1C of about 7%, inverting the ADA equation. Worth knowing: this is an estimate from an average, and a laboratory A1C measures something related but not identical, so the two will not always agree. Bring the actual lab report to your clinician.

Glucose unit
Defaulted from your region (United States).
Average glucose to A1C
eAG (mg/dL)eAG (mmol/L)A1C (NGSP %)IFCC (mmol/mol)
1116.25.5%37
12676.0%42
1407.86.5%48
1548.57.0%53
1699.47.5%58
18310.28.0%64
19710.98.5%69
21211.89.0%75
Inverting eAG = 28.7 × A1C − 46.7 (Nathan 2008). Rows are chosen at half-point A1C intervals, so the glucose column steps unevenly.

Going the other way — a lab A1C into an average glucose — is the A1C calculator. If your average comes from a CGM rather than a meter, the GMI calculator uses the equation designed for CGM data.

This converts an average blood glucose reading into the A1C percentage it corresponds to, by inverting the ADA equation from the ADAG study. Enter a meter or CGM average in mg/dL or mmol/L and it returns the equivalent A1C in both NGSP percent and IFCC units, with the ADA range named.

  • Estimated average glucose (ADAG / Nathan) — eAG (mg/dL) = 28.7 x A1C - 46.7. Verified against Nathan et al., Diabetes Care 2008 (ADAG study) (A population regression: in the ADAG study, individuals at the same A1C had meaningfully different mean glucose. The A1C assay itself carries about +/- 0.5 percentage points under NGSP certification.)
  • NGSP percent to IFCC mmol/mol — IFCC (mmol/mol) = (NGSP % - 2.15) x 10.929. Verified against NGSP - IFCC standardisation and the NGSP/IFCC master equation (The master equation is periodically re-derived from network comparison data; treat converted values as approximate.)

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Frequently asked questions

How do you work out A1C from average blood sugar?
Add 46.7 to your average glucose in mg/dL and divide by 28.7. That is the ADA equation from Nathan 2008 rearranged. An average of 154 mg/dL gives an A1C of about 7.0%.
Will this match my lab A1C?
Often closely, but not always. A lab A1C measures glycated hemoglobin directly, while this estimates A1C from an average of glucose readings. Differences in how often you measured, and conditions that affect red blood cells, can move the two apart.
What average glucose corresponds to an A1C of 6.5%?
About 140 mg/dL, or 7.8 mmol/L. The ADA uses an A1C of 6.5% and above as one of its diagnostic criteria for diabetes, normally with a confirmatory test.
Can I use a single glucose reading?
No — the equation takes an average. A single fingerstick reflects one moment and can sit far from your average in either direction. Use the average your meter or CGM reports over a period.
My readings are in mmol/L. Does that work?
Yes. Switch the unit above and the conversion runs on the mg/dL equivalent, so entering 8.6 mmol/L and entering 154 mg/dL give the same A1C.

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The next number

No body metric means much on its own. Here is what this one feeds into.

A1C calculatorThe forward direction, plus the full conversion table and per-value pages.GMI calculatorThe CGM-specific equation, and the gap between it and a lab A1C.

Related calculators

A1C calculatorGlycemic markersGMI calculatorGlycemic markers

Every formula on this page is listed with its source on the methodology page, and changes to any reference value are logged in the data changelog. Canonical URL: https://myhealthmywellness.com/glucose-to-a1c-calculator

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