Vial to Units

Peptide Calculator

Enter the vial size, the bacteriostatic water you added and your prescribed dose. Get the concentration and the exact number of units to draw on an insulin syringe.

mg
mL

Enter the vial size and the water you added.

Arithmetic only. This tool does not recommend a dose; use the one your prescriber gave you.

Calculators by peptide

How the maths works

Reconstitution is three steps of arithmetic. The calculator does exactly this and nothing else.

concentration (mg/mL) = amount in vial (mg) ÷ water added (mL) volume to draw (mL) = dose (mg) ÷ concentration (mg/mL) syringe units = volume (mL) × 100 (U-100 syringe: 100 units = 1 mL)

Step-by-step explanation with a worked concentration example

Common conversions

Questions

How do I calculate how many units to draw?

Divide the amount in the vial by the water you added to get the concentration. Divide your prescribed dose by that concentration to get millilitres, then multiply by 100 to get units on a U-100 insulin syringe. A 10 mg vial mixed with 2 mL is 5 mg/mL, so each 10 units holds 0.5 mg.

What does "units" mean on an insulin syringe?

On a U-100 syringe, 100 units is 1 mL, so 1 unit is 0.01 mL. Units measure volume, not the amount of peptide. How many milligrams are in a unit depends entirely on how much water was added to the vial.

Does adding more water change the dose?

No. More water makes the solution weaker, so the same dose takes up more units on the syringe. The amount of peptide in the vial stays the same.

How do I convert mcg to mg?

Divide by 1,000. 250 mcg is 0.25 mg. The calculator accepts either.

Does this calculator tell me what dose to take?

No. It only converts a dose you already have into a volume and a syringe marking. Your dose comes from your prescriber.