Unit converter
Dosage unit converter
Convert a labeled amount between units when the conversion is defined.
This changes units. A matching number is not a matching effect, and it is not a dose to take.
Questions
Are equal units the same effect?
No. A matching number is not a matching effect, and it is not a dose to take.
What if the IU source is unknown?
The converter shows an error and no number.
How this number is made
What this result means
The result is the same amount in another unit. Retinol, supplemental beta-carotene, and dietary beta-carotene stay separate even when two of those factors match.
Formula and methodology
Grams, milligrams, and micrograms move by exact powers of 1,000. Vitamin D uses 1 IU = 0.025 mcg. Retinol and supplemental beta-carotene each use 1 IU = 0.3 mcg RAE. Dietary beta-carotene uses 1 IU = 0.05 mcg RAE. Natural vitamin E uses 1 IU = 0.67 mg. Synthetic vitamin E uses 1 IU = 0.45 mg.
Worked example
1,000 mg is 1 g. 40 IU of vitamin D is 1 mcg. 10 IU of retinol is 3 mcg RAE. 20 IU of dietary beta-carotene is 1 mcg RAE. 100 IU of natural vitamin E is 67 mg, and 100 IU of synthetic vitamin E is 45 mg.
Assumptions and limitations
An unknown source is not converted. The page does not read a dose from a product name.
Who should not rely on the result
Anyone looking for a dose to take should not use this result as that instruction.
Sources
- NIST metric SI prefixes. Accessed 2026-10-02.
- NIH ODS Vitamin D consumer fact sheet. Accessed 2026-10-02.
- NIH ODS Vitamin A health professional fact sheet. Accessed 2026-10-02.
- NIH ODS Vitamin E health professional fact sheet. Accessed 2026-10-02.