Units converter (mg to U-100 syringe units)

U-100 syringe sizes

Every U-100 insulin syringe uses the same scale, 100 units per mL, so one unit is always 0.01 mL; only the barrel capacity differs. Choose a barrel that holds the full volume, because splitting a draw doubles the measuring error.

Micrograms: 1 mg = 1,000 mcg, so at 2.5 mg/mL each unit holds 25 mcg. Syringe units are not International Units (IU): IU measure biological activity and are defined per drug, as on hCG or somatropin labels.

Worked example

Example: 0.5 mg at 2.5 mg/mL → 0.5 ÷ 2.5 = 0.2 mL → 0.2 × 100 = 20 units.

How it works

1. 1. Find the concentration

   Read the concentration in mg/mL (from your own reconstitution arithmetic or the product documentation).

2. 2. Convert mass to volume

   Divide the mass in mg by the concentration in mg/mL to get milliliters.

3. 3. Convert volume to units

   Multiply milliliters by 100: a U-100 syringe has 100 units per mL.

Frequently asked questions

Sources

1. Reconstitution, units and concentration arithmetic: see our lab-handling guide, The Peptide Directory

Label and trial dose references

For doses as printed in FDA labels or used in trials, see the peptide dose reference and the protocol pages.

Related tools

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• Peptide CalculatorA 10 mg vial with 2 mL of diluent is 5 mg/mL, so 0.25 mg occupies 0.05 mL — 5 units on a U-100 syringe.
• Titration Vial PlannerFour steps of 4 uses at 0.25, 0.5, 1 and 1.7 mg total 13.8 mg, which is two 10 mg vials (rounded up).
• Semaglutide Units ConverterAt a concentration of 2.5 mg/mL, 0.25 mg of semaglutide is 0.1 mL, which is 10 units on a U-100 syringe.
• Tirzepatide Units ConverterAt 10 mg/mL, 2.5 mg of tirzepatide is 0.25 mL, which is 25 units on a U-100 syringe.
• Semaglutide Reconstitution CalculatorA 5 mg semaglutide vial reconstituted with 2 mL of diluent has a concentration of 2.5 mg/mL.
• Tirzepatide Reconstitution CalculatorA 30 mg tirzepatide vial reconstituted with 3 mL of diluent has a concentration of 10 mg/mL.
• Retatrutide CalculatorA 10 mg retatrutide vial with 2 mL of diluent is 5 mg/mL, so 1 mg is 0.2 mL — 20 units on a U-100 syringe.
• BAC Water CalculatorTo make 5 mg/mL from a 10 mg vial, add 2 mL of bacteriostatic water (10 ÷ 5 = 2).