How to Convert Insulin µIU/mL to pmol/L
Insulin is reported in µIU/mL (or mU/L) in the US and in pmol/L across much of the world. The conversion multiplies µIU/mL by a factor — and here is the catch most converters hide.
Insulin pmol/L = insulin µIU/mL × 6.0 (or × 6.945) Insulin µIU/mL = insulin pmol/L ÷ 6.0 (or ÷ 6.945) Which Factor: 6.0 or 6.945?
You will see both. The widely copied online value is 6.945, but that came from an assumed molar mass of 6,000. Human insulin actually has a molar mass of 5,808, which gives a factor of about 6.0 — the value supported by insulin standardization research. The difference is roughly 15%, which matters near decision thresholds. This tool defaults to 6.0 and lets you switch to 6.945 to match a specific source; either way, compare against your own lab's range.
Insulin µIU/mL to pmol/L Chart
| µIU/mL (mU/L) | pmol/L (×6.0) | pmol/L (×6.945) | Context |
|---|---|---|---|
| 2.6 µIU/mL | 16 pmol/L | 18 pmol/L | Lower normal (fasting) |
| 5 µIU/mL | 30 pmol/L | 35 pmol/L | Insulin-sensitive |
| 10 µIU/mL | 60 pmol/L | 69 pmol/L | Upper "optimal" |
| 25 µIU/mL | 150 pmol/L | 174 pmol/L | Upper normal |
| 30 µIU/mL | 180 pmol/L | 208 pmol/L | High (insulin resistance) |
| 50 µIU/mL | 300 pmol/L | 347 pmol/L | Markedly high |
Fasting Insulin Reference Ranges
| Category | µIU/mL | pmol/L (×6.0) |
|---|---|---|
| Optimal / insulin-sensitive | Below 10 µIU/mL | Below 60 pmol/L |
| Normal (fasting) | 2.6 – 24.9 µIU/mL | 16 – 150 pmol/L |
| High (hyperinsulinemia) | Above 25 µIU/mL | Above 150 pmol/L |
Ranges vary by lab and assay; many clinicians view fasting insulin under about 10 µIU/mL as more insulin-sensitive.
Insulin and HOMA-IR (Insulin Resistance)
A fasting insulin on its own tells only part of the story. Insulin resistance is better estimated by combining fasting insulin with fasting glucose in the HOMA-IR calculation. If you are looking at insulin to assess insulin resistance, run the numbers through the HOMA-IR calculator, and convert your glucose if needed on the glucose conversion calculator.
Worked Example
Suppose a report shows 180 pmol/L insulin and you want µIU/mL (using 6.0):
180 ÷ 6.0 = 30 µIU/mL 30 µIU/mL is above the usual fasting range, consistent with hyperinsulinemia. With the 6.945 factor the same 180 pmol/L would be about 26 µIU/mL — which is why the factor matters.
Frequently Asked Questions
How do you convert insulin µIU/mL to pmol/L?
Multiply µIU/mL by 6.0 (or 6.945). For example, 10 µIU/mL is about 60 pmol/L.
Is µIU/mL the same as mU/L?
Yes — µIU/mL, mU/L and mIU/L are identical (1:1) for insulin.
What is a normal fasting insulin?
About 2.6–24.9 µIU/mL (16–150 pmol/L); under 10 is often considered optimal.
Which factor should I use?
6.0 is best supported; 6.945 is common online. Match your source and lab range.
References
- NCBI/PMC — Insulin units and conversion factors (6.0 vs 6.945).
- Insulin µIU/mL = mU/L (1:1); factor 6.0 (MW 5,808) or 6.945 (assumed MW 6,000); fasting reference range 2.6–24.9 µIU/mL.
Conclusion
Converting insulin between µIU/mL and pmol/L is a simple multiply — but by which factor? 6.0 is the better-supported value, 6.945 is the common one, and the ~15% gap can matter. Pick the factor that matches your source, and read insulin alongside glucose and HOMA-IR.