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The Calculator

Syringe units, mg and mcg explained

Last updated 11 days ago

"Units" on an insulin syringe measure volume. They aren't the same as IU, and they aren't the same as mg or mcg. The Calculator assumes U-100 syringes, where 100 units equals 1 mL.

Syringe units

The Calculator's "Syringe Size" options are U-100 insulin syringes:

  • "0.3 mL" (30 units)
  • "0.5 mL" (50 units)
  • "1.0 mL" (100 units)

On these, 100 units always equals 1 mL. Other kinds of syringe, such as U-40 or U-50, mark units differently, so the Calculator's results won't match them. Check the label on your syringe.

Units are not IU

  • Syringe units are marks for how much liquid is in the syringe.
  • IU (international units) describe the strength of some medicines, and appear on some product labels.

The two aren't related. Peptimes' Calculator doesn't work in IU. When you log a dose of a compound measured in IU, enter it in IU and Peptimes keeps it in IU.

mg and mcg

  • 1 mg (milligram) = 1,000 mcg (micrograms).
  • The Calculator's "MG" / "MCG" switch converts your number, so the amount stays the same.
  • When you log or schedule a dose, check the unit before you save.

Not sure?

If you're unsure which syringe you have, or how to read it, ask your pharmacist or clinician. Don't guess.

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