IU Calculator

Work out dose volume for IU-marked peptides like HGH. Converts IU to mg using your vial's potency.

Last reviewed 2 May 2026

Vial strength (IU)

Total IU in the vial. Most HGH vials are 10 IU or 12 IU.

Potency (IU per mg)

HGH is typically 3 IU/mg. Some peptides differ. Read your vial label.

BAC water added (mL)

Volume of bacteriostatic water you reconstituted with.

Dose (IU)

The dose your prescriber specified, in IU.

Syringe diagram showing the pull line

How the IU maths works

Some peptides are labelled in international units (IU) rather than milligrams. To turn an IU dose into a syringe draw, the calculator uses your vial's potency - the IU-per-milligram figure - to work out the concentration in IU per millilitre once the bacteriostatic water is added. Your dose in IU divided by that concentration gives the millilitres to draw, and multiplying by 100 reads the units on a U-100 insulin syringe.

The amount of bacteriostatic water you add sets how concentrated the solution is: more water means a larger, easier-to-read draw for the same dose, less water means a smaller one. Enter the volume you actually used so the result matches your vial.

Choosing a diluent

Bacteriostatic water - sterile water with 0.9% benzyl alcohol - suits a multi-dose vial, as the preservative allows repeated draws over about 28 days refrigerated. Sterile water has no preservative and makes a single-use vial. A 0.9% sodium chloride (saline) diluent is sometimes chosen to reduce stinging at the injection site. Follow your pharmacy label for the right one.

IU calculator FAQ

What potency should I use?

Whatever your vial states. HGH is 3 IU/mg by convention, which is the default here, but other IU-marked peptides can differ - read the label and adjust if needed.

What is the difference between this and the HGH calculator?

They do the same maths; the HGH calculator simply defaults to HGH's 3 IU/mg potency and wording. Use this one for non-HGH IU-marked peptides.

Which syringe do the units assume?

A U-100 insulin syringe, where 1 mL is 100 units. Check the markings on your own syringe before drawing.

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