About this tool

Vitamin IU to Microgram Converter

Convert vitamin A, D and E between IU and micrograms using the official per-form factors, with Daily Value and upper-limit context.

The Vitamin IU to Microgram Converter turns an International Unit figure on a supplement label into micrograms or milligrams using the specific factor for that vitamin and chemical form, because an IU is defined separately for each one. It covers vitamin D (1 IU = 0.025 mcg), vitamin A as retinol or as carotenoids (0.3 down to 0.025 mcg RAE per IU) and vitamin E in natural and synthetic forms (0.67 mg and 0.45 mg per IU), and reports the result against the Daily Value and the adult tolerable upper intake level. Useful for anyone reading an older label in IU next to a newer one in micrograms.

How to use Vitamin IU to Microgram Converter

1. 1

   Open Vitamin IU to Microgram Converter on AltFTool — it loads instantly in your browser.

2. 2

   Enter the values you already know.

3. 3

   Fine-tune the options to match your scenario.

4. 4

   Read the result and use it in your planning or reporting.

Why use Vitamin IU to Microgram Converter

• Per-form factors

  Separate factors for retinol, supplemental and dietary carotenoids, D2/D3, and natural versus synthetic vitamin E.

• Upper-limit awareness

  Flags doses above the adult tolerable upper intake level instead of just printing a number.

• Both directions

  Enter IU, mcg or mg and get the other two, with the Daily Value percentage alongside.

Common use cases

• Check whether a 60,000 IU weekly vitamin D sachet is above the 4000 IU per day upper limit when spread across the week.
• Compare a natural d-alpha-tocopherol vitamin E capsule in IU against a newer label that lists milligrams.
• Translate an older 5000 IU vitamin A label into mcg RAE so it can be compared with the 900 mcg Daily Value.
• Work out how many IU a doctor's instruction of 50 mcg of vitamin D per day actually means on the bottle you own.

Frequently asked questions