The Peptide Calculator

Syringe units and volume

A unit is not a volume until you know the barrel. This converts in both directions and shows every listed scale together.

Educational arithmetic only. Not medical advice and not a dosing protocol.

No default: the same volume reads differently on each.

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Read this with the answer

This is educational arithmetic on figures entered by the reader. It is not medical advice, not a dosing protocol, and not a recommendation that anything be prepared, obtained or administered.

Nothing here states what quantity is appropriate for anyone, and there is no function in it that produces an amount to administer. A question about anyone’s health belongs with a licensed clinician who can examine the person asking.

Most compounds named here are research chemicals that are not approved by the FDA for human use. An exact calculation is not an accurate measurement: what is actually in a syringe depends on the preparation and the device, neither of which this page can see.

No qualified clinical reviewer is recorded against this site, and no credential is claimed anywhere on it. Full disclaimer.

Show the working
  1. units = volume in mL × units per mL. The calibration is printed on the barrel: U-100 carries 100 units per millilitre, U-50 carries 50, U-40 carries 40.
  2. So one volume has three different unit readings, and one unit reading means three different volumes. 20 units is 0.2 mL at U-100, 0.4 mL at U-50 and 0.5 mL at U-40.
  3. The nearest printed mark is the exact figure rounded to the barrel’s smallest graduation, half away from zero. A 1 mL U-100 barrel is normally marked every single unit.

Why "units" is the most dangerous word in this arithmetic

Milligrams and millilitres mean the same thing everywhere. A unit does not. It is a mark on a particular barrel, and the volume behind it depends entirely on how that barrel was calibrated. The same printed 20 is 0.2 mL, 0.4 mL or 0.5 mL depending on which syringe is in the drawer.

U-100 is the most common calibration in most markets, which is exactly why assuming it is hazardous: the assumption is right often enough to go unnoticed and wrong by a factor of two or two and a half when it fails. Nothing in the answer would look different.

What the calibration describes, and what it does not

The calibration is a property of the device. A U-100 barrel is marked so that 100 of its units fill one millilitre, and that is all the number says. It carries no information about what is in the syringe, how strong it is, or whether any particular reading is appropriate for anything.

The capacity figures matter too. A 0.3 mL U-100 barrel holds 30 units, so a draw of 40 units cannot be taken on it in one go however the arithmetic comes out, and the answer says so rather than printing a number the device cannot deliver.

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