IFCC to NGSP HbA1c Converter
Convert HbA1c between IFCC units (mmol/mol) and NGSP units (%). Bidirectional — enter either value.
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IFCC vs. NGSP: Understanding the Difference
There are two standardized systems for reporting HbA1c results. The NGSP system, used primarily in the United States, reports A1C as a percentage (%). The IFCC system, adopted by many countries worldwide, reports HbA1c in millimoles per mole (mmol/mol).
Both systems measure the same thing — the proportion of glycated hemoglobin in your blood — but use different analytical methods and reference ranges. The IFCC method is considered more specific and precise, but the NGSP format is more widely recognized by patients and many clinicians.
Conversion Formulas
IFCC to NGSP Conversion Table
| IFCC (mmol/mol) | NGSP (%) | Category |
|---|---|---|
| 20 | 4.0% | Normal |
| 25 | 4.4% | Normal |
| 30 | 4.9% | Normal |
| 35 | 5.4% | Normal |
| 40 | 5.8% | Prediabetes |
| 45 | 6.3% | Prediabetes |
| 50 | 6.7% | Diabetes |
| 55 | 7.2% | Diabetes |
| 60 | 7.6% | Diabetes |
| 65 | 8.1% | Diabetes |
| 70 | 8.6% | Diabetes |
| 75 | 9.0% | Diabetes |
| 80 | 9.5% | Diabetes |
| 85 | 9.9% | Diabetes |
| 90 | 10.4% | Diabetes |
| 95 | 10.8% | Diabetes |
| 100 | 11.3% | Diabetes |
| 105 | 11.8% | Diabetes |
| 110 | 12.2% | Diabetes |
| 115 | 12.7% | Diabetes |
| 120 | 13.1% | Diabetes |
Key Diagnostic Thresholds in Both Units
Understanding the IFCC and NGSP equivalents for key diagnostic cutoffs is essential for interpreting your HbA1c results regardless of which system your laboratory uses:
Which Countries Use Which System?
NGSP (%) — Percentage
United States, Japan (JDS/NGSP), and some countries that report in both units. This is the format most familiar to US patients and is used in ADA guidelines.
IFCC (mmol/mol) — SI Units
United Kingdom, most of Europe, Australia, New Zealand, and many countries in Asia and South America. Increasingly adopted worldwide as the global standard.
Why Understanding Both Units Matters
If you travel internationally or see doctors in different countries, you may receive lab reports using either the IFCC or NGSP system. Being able to interpret both formats ensures you understand your results no matter where you are tested. International lab reports do not always include a conversion, so knowing how to translate between units is a practical skill.
Many CGM devices and diabetes management apps allow users to choose their preferred HbA1c display unit. If your device defaults to mmol/mol and you are accustomed to percentages, or vice versa, understanding the relationship between the two prevents confusion when reviewing your glucose trends and reports.
Additionally, medical literature and research studies use both systems, though IFCC units are increasingly standard in peer-reviewed publications. Patients who read research about new treatments or clinical trial outcomes need to recognize both formats to accurately evaluate findings. Knowing both units helps you avoid misinterpretation of results and have more informed conversations with your healthcare team about your A1C targets and progress.
Frequently Asked Questions
What is the difference between IFCC and NGSP?
IFCC (International Federation of Clinical Chemistry) reports HbA1c in mmol/mol. NGSP (National Glycohemoglobin Standardization Program) reports HbA1c as a percentage (%). Both measure the same thing but use different units and scales. The NGSP system is used primarily in the US, while many other countries use IFCC or report both.
How do I convert IFCC to NGSP?
Use the formula: NGSP (%) = 0.09148 × IFCC (mmol/mol) + 2.152. For example, an IFCC value of 48 mmol/mol equals an NGSP value of 6.5% (the diabetes diagnostic threshold).
Which countries use IFCC vs NGSP?
The US primarily uses NGSP (%). Most European countries, Australia, and many Asian countries use IFCC (mmol/mol) or report both values. The UK switched to dual reporting in 2009. Japan and some countries use their own reference methods but align with NGSP.