mcg to IU Converter by Omni Calculator
| Micrograms (mcg) Converted to | International Units (IU) |
|---|---|
| 10 mcg | 400 IU |
| 15 mcg | 600 IU |
| 25 mcg | 1000 IU |
| 30 mcg | 1200 IU |
| 40 mcg | 1600 IU |
| 50 mcg | 2000 IU |
| 100 mcg | 4000 IU |
| 125 mcg | 5000 IU |
| 900 mcg | 36000 IU |
| 1000 mcg | 40000 IU |
| 2400 mcg | 96000 IU |
| 2.5 mcg | 100 IU |
| 23 mcg | 920 IU |
| 0.25 mcg | 10 IU |
mcg to IU Conversion Chart
| Substance | 1 IU equals | 1 mcg equals | Notes |
|---|---|---|---|
| Vitamin D | 0.025 mcg | 40 IU | Applies to both D2 and D3 forms |
| Vitamin A | 0.3 mcg | 3.33 IU | For retinol form |
| Vitamin E | 0.67 mg | 1.49 IU | For d-alpha-tocopherol form |
| Vitamin K | 1 mcg | 1 IU | Rare case where 1 IU = 1 mcg |
| Insulin | 0.0347 mg | 28.8 IU | For regular human insulin |
| Heparin | Varies | Varies | Depends on specific preparation |
| Penicillin G | 0.6 mcg | 1.67 IU | For sodium penicillin G |
How many mcg are in an IU?
1 IU of vitamin D is defined as 0.025 mcg of cholecalciferol (vitamin D3) or ergocalciferol (vitamin D2).
Therefore:
- 1 IU of vitamin D = 0.025 mcg
- 1 mcg of vitamin D = 40 IU
For vitamin A, the conversion is different:
1 IU of vitamin A is defined as 0.3 mcg of retinol or 0.6 mcg of beta-carotene.
So:
- 1 IU of vitamin A (as retinol) = 0.3 mcg
- 1 mcg of vitamin A (as retinol) = 3.33 IU
mcg to IU Conversion Formula
The formula for converting between mcg and IU is:
IU = mcg ÷ (mcg per IU)or
mcg = IU × (mcg per IU)The key is knowing the specific mcg per IU value for the substance in question. Let’s look at two examples:
Convert 1000 mcg of vitamin D to IU
- mcg per IU for vitamin D = 0.025
- IU = 1000 ÷ 0.025 = 40,000 IU
Convert 5000 IU of vitamin A to mcg
- mcg per IU for vitamin A (retinol) = 0.3
- mcg = 5000 × 0.3 = 1500 mcg
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