IU to mg converter

Pick what you are converting and type the amount in IU, mg or mcg. Only substances with an official factor are listed.

mg = IU ÷ the official IU per mg for that substance

Substance

Amount

This does arithmetic on the numbers you type. It doesn't suggest a dose. Check the result with your prescriber or pharmacist.

That's

–mg

Type an amount

Worked example

With 3 IU in each mg, 12 IU ÷ 3 = 4 mg, and 4 mg × 3 = 12 IU.

With 40 IU in each mcg, 1,000 IU ÷ 40 = 25 mcg.

How the math works

An IU measures a substance's activity, not its weight. Each substance has its own IU, so the page uses the factor an official standard sets for it and nothing else.

It's the same code the PepBloom app runs, and it runs in your browser. Nothing you type leaves this page.

Official factors

Substance	IU in each mg	Source
Somatropin (HGH)	3	WHO International Standard 98/574
Vitamin D (D2 or D3)	40,000	FDA, 40 in each mcg

Anything without an official factor is left out, because its IU can't be turned into mg. That includes hCG: its labels give amounts in USP units only (Novarel label), and no standard sets a mass for them.

Questions

How do I convert IU to mg?

Divide the IU by the IU in each mg for that exact substance. That only works where an official standard sets the factor, such as the ones in the table above.

Can I convert hCG IU to mg?

No. hCG has no official factor, and its labels give amounts in units only. So any mg figure for hCG IU isn't an official one.

Is an IU the same as a unit on a syringe?

No. A unit on a U-100 syringe is a volume, 0.01 mL. An IU is an amount of activity. To turn IU into syringe units, use the peptide calculator with an IU vial.

Sources

somatropin (HGH) · hCG · mcg to mg · Peptide calculator