Enter the concentration in nmol/L and select the analyte to determine the equivalent concentration in IU/mL. Because IU is defined differently for each substance, the conversion depends on the analyte you choose.

nmol/L to IU/mL Converter

Enter a value, choose the analyte, then click Calculate.

nmol/L → IU/mL
IU/mL → nmol/L

nmol/L to IU/mL Formula

The following formula is used to convert a concentration in nmol/L to IU/mL for a specific analyte.

IU/mL = (NMOL / 1000) / NPIU

Variables:

  • IU/mL is the concentration in international units per milliliter
  • NMOL is the concentration in nanomoles per liter
  • NPIU is the number of nanomoles corresponding to 1 IU for the selected analyte

To calculate IU/mL, first divide the nmol/L value by 1000 to convert from liters to milliliters, then divide by the analyte-specific nanomoles-per-IU factor.

Common nmol per IU Factors

This converter uses the following approximate analyte-specific relationships.

AnalyteApprox. nmol per IU10 nmol/L in IU/mL
Vitamin D₃ (cholecalciferol)0.064970.1539 IU/mL
Vitamin A (retinol)1.0470.00955 IU/mL
Vitamin E (d-α-tocopherol)1555.90.00000642 IU/mL
Insulin (human)5.970.00168 IU/mL

What is nmol/L to IU/mL Conversion?

Nanomoles per liter (nmol/L) is a chemical concentration unit based on amount of substance, while international units per milliliter (IU/mL) is based on biological activity. Because an IU is defined separately for each vitamin, hormone, or compound, there is no single universal conversion between nmol/L and IU/mL. The correct result depends on the analyte and its official IU definition.

For example, vitamin D₃ has a much smaller nmol-per-IU factor than vitamin E, so the same nmol/L value gives a much larger IU/mL result for vitamin D₃ than for vitamin E. This is why analyte selection is essential when performing this conversion.

How to Calculate nmol/L to IU/mL?

The following steps outline how to convert nmol/L to IU/mL.


  1. First, determine the concentration in nanomoles per liter (nmol/L).
  2. Next, identify the analyte and its approximate nanomoles-per-IU factor.
  3. Divide the nmol/L value by 1000 to convert the concentration to nmol/mL.
  4. Finally, divide that result by the analyte’s nmol-per-IU factor to find IU/mL.
  5. After inserting the values and calculating the result, check your answer with the converter above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Concentration (NMOL) = 10 nmol/L

Analyte = Vitamin D₃ (cholecalciferol)

nmol per IU (NPIU) = 0.06497

IU/mL = (10 / 1000) / 0.06497 = 0.1539 IU/mL

This means a vitamin D₃ concentration of 10 nmol/L is approximately 0.1539 IU/mL.