mcg to IU Converter
Convert between micrograms (mcg) and International Units (IU) for vitamins, hormones, and other substances
Convert Between mcg and IU
Enter the microgram value you want to convert
Different substances have unique conversion factors
Medical Disclaimer
This calculator is for educational purposes only. Always consult healthcare professionals for medical decisions. Dosage requirements vary by individual circumstances, health conditions, and other medications.
Conversion Factors Reference
| Substance | IU per mcg | Example: 100 mcg | Example: 1000 IU |
|---|---|---|---|
Vitamin D (D2/D3) Fat-soluble vitamins | 40 | 4,000 IU | 25.0 mcg |
Vitamin A (Retinol) Fat-soluble vitamins | 3.33 | 333 IU | 300.3 mcg |
Vitamin A (Retinyl Palmitate) Fat-soluble vitamins | 1.82 | 182 IU | 549.5 mcg |
Vitamin A (Beta-Carotene) Fat-soluble vitamins | 1.67 | 167 IU | 598.8 mcg |
Vitamin A (Retinyl Acetate) Fat-soluble vitamins | 2.91 | 291 IU | 343.6 mcg |
Vitamin A (Retinyl Propionate) Fat-soluble vitamins | 2.79 | 279 IU | 358.4 mcg |
Vitamin E (Alpha-Tocopherol) Fat-soluble vitamins | 1.49 | 149 IU | 671.1 mcg |
Vitamin E (dl-Alpha-Tocopherol) Fat-soluble vitamins | 1.1 | 110 IU | 909.1 mcg |
Insulin Hormones | 24 | 2,400 IU | 41.7 mcg |
hCG (Human Chorionic Gonadotropin) Hormones | 10 | 1,000 IU | 100.0 mcg |
FSH (Follicle Stimulating Hormone) Hormones | 150 | 15,000 IU | 6.7 mcg |
LH (Luteinizing Hormone) Hormones | 100 | 10,000 IU | 10.0 mcg |
Growth Hormone (Somatropin) Hormones | 3 | 300 IU | 333.3 mcg |
Quick Facts About IU
International Unit
Measures biological activity, not weight
Microgram
Unit of mass (1/1,000,000 of a gram)
Not Universal
Conversion varies by substance type
Common Conversions
Understanding mcg to IU Conversions
What is an International Unit (IU)?
An International Unit (IU) is a measurement of the biological activity or potency of a substance, rather than its physical weight. The IU system was developed to standardize dosing across different forms of vitamins, hormones, and medications that may have varying potencies.
Why Different Conversion Factors?
Each substance has a unique conversion factor because the biological activity per unit of weight varies significantly. For example, synthetic forms of vitamins may have different potencies than natural forms, requiring different conversion factors.
Common Applications
Vitamin Supplements:
Vitamins A, D, and E are commonly measured in IU
Medical Applications:
Insulin, hCG, and other hormones use IU dosing
Therapeutic Doses:
Standardized potency across manufacturers
Important: Always verify dosage information with healthcare providers. This calculator provides conversions based on established international standards, but individual needs may vary based on health conditions and other factors.