PeptideWise

Injection Volume Calculator

Estimates the volume in mL to draw for a target peptide dose, given a reconstituted vial concentration. Output includes equivalent unit readings on U-100, U-50, and U-30 insulin syringes for side-by-side comparison.

Vial mass
Reconstitution volume (mL)
Target dose

Estimated injection volume

Concentration
2.500 mg / mL

2500 mcg / mL

Injection volume
0.100 mL
Equivalent units on insulin syringes
U-100 syringe10.0 units
U-50 syringe10.0 units
U-30 syringe10.0 units

These figures are estimates based on standard formulas. Always verify with your prescriber and the peptide compounding label.

How the calculation works

The calculator follows the standard concentration formula:concentration = vial mass / reconstitution volume. From that concentration, the volume needed for a target dose isvolume = target dose / concentration.

Example: a 10 mg semaglutide vial reconstituted with 2 mL of bacteriostatic water yields a 5 mg/mL solution. A 0.25 mg target dose at that concentration is 0.05 mL — 5 units on a U-100 syringe.

Limitations

  • Estimates assume the labeled vial mass is exact and uniformly dissolved.
  • Dead volume in the syringe and needle is not accounted for.
  • The calculator does not validate the safety or appropriateness of your target dose.
  • For informational purposes only. Not a substitute for professional medical advice.

Sources

  1. USP <797> Pharmaceutical Compounding — Sterile Preparations. United States Pharmacopeia.
  2. Handbook on Injectable Drugs. American Society of Health-System Pharmacists.

Frequently Asked Questions

What is the difference between this and the syringe unit converter?
The Injection Volume Calculator outputs a draw volume in mL plus equivalent units on U-100, U-50, and U-30 syringes side-by-side. The Syringe Unit Converter is focused on a single chosen syringe and returns the unit reading for that specific barrel. Use this one to compare which syringe size is best for your dose.
Why does the calculator show concentration in mg/mL?
Concentration in mg/mL is the standard way pharmaceutical labels express reconstituted strength (e.g. "2.5 mg/mL"). The calculator also shows mcg/mL for peptides typically dosed in micrograms.
What is "draw volume" vs "injection volume"?
In this tool they are the same: the volume of reconstituted solution drawn from the vial into the syringe for a single administration. Real-world draws also include a small dead-volume amount that stays in the syringe and needle hub; this calculator does not account for that.
Why do U-100 and U-50 syringes show the same unit count?
Both U-100 and U-50 insulin syringes use the same units-per-mL scale (100 units = 1 mL). A U-50 syringe is just a shorter barrel — its maximum draw is 0.5 mL (50 units) instead of 1 mL. U-30 likewise uses the 100 units/mL scale, capped at 0.3 mL.
What if my target dose requires less than 0.05 mL?
Very small draws are difficult to measure accurately on a 1 mL syringe. Switch to a 0.3 mL (U-30) syringe for better precision, or reconstitute the vial with more bacteriostatic water to bring the per-dose volume above 0.10 mL. Discuss volumes below ~5 units with a pharmacist.