IU ↔ mg/mcg Vitamin Converter
Convert vitamins A, D and E between International Units and mass — each vitamin has its own conversion.
IU measures *activity*, not mass, so there's no universal factor — and crucially, vitamin E's natural form (d-alpha) carries ~50% more activity per mg than synthetic (dl-alpha), a real label trap. Anchors: 1000 IU vitamin D = 25 mcg; 400 IU natural vitamin E ≈ 268 mg. Modern labels increasingly use mass (mcg/mg) because IU caused exactly this confusion.
Formula
Reference aid for healthcare professionals only. Every result must be independently verified before clinical use. Never use this tool for self-medication or to replace clinical judgement.
Convert vitamins A, D and E between International Units and mass — each vitamin has its own conversion. The IU ↔ mg/mcg Vitamin Converter is a free, private iu to mg tool — every result computes instantly in your browser with no sign-up and no data upload.
About IU ↔ mg/mcg Vitamin Converter
IU measures *activity*, not mass, so there's no universal factor — and crucially, vitamin E's natural form (d-alpha) carries ~50% more activity per mg than synthetic (dl-alpha), a real label trap. It applies IU is biological-activity based — each vitamin has a unique IU↔mass factor. Use the IU ↔ mg/mcg Vitamin Converter to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use IU ↔ mg/mcg Vitamin Converter
- 1Enter your details in the IU ↔ mg/mcg Vitamin Converter input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use IU ↔ mg/mcg Vitamin Converter?
- ✓Instant iu to mg result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (IOM Dietary Reference Intakes — IU conversion factors)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the IU ↔ mg/mcg Vitamin Converter work?+
IU measures *activity*, not mass, so there's no universal factor — and crucially, vitamin E's natural form (d-alpha) carries ~50% more activity per mg than synthetic (dl-alpha), a real label trap. The calculation uses the formula: IU is biological-activity based — each vitamin has a unique IU↔mass factor. Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the IU ↔ mg/mcg Vitamin Converter accurate, and what is it based on?+
The method is traceable to authoritative sources: IOM Dietary Reference Intakes — IU conversion factors. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the IU ↔ mg/mcg Vitamin Converter free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This is a reference aid for healthcare professionals and must be independently verified. It is not for self-diagnosis or self-medication.
What can I use the IU ↔ mg/mcg Vitamin Converter for?+
It's commonly used for iu to mg, vitamin d iu to mcg, vitamin e iu to mg. Convert vitamins A, D and E between International Units and mass — each vitamin has its own conversion.
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