Free research tool
Peptide Reconstitution Calculator
Enter your vial size, the bacteriostatic water you're adding and your target amount — get the exact concentration, the volume to draw and the reading in insulin-syringe units, instantly. For laboratory research use only.
Your vial
Draw this much
Fill to 10 units on a U-100 insulin syringe
For laboratory research and measurement only — not medical advice, and not for human or veterinary use. Always verify calculations independently.
How the peptide calculator works
Reconstitution is simply mixing a lyophilised (freeze-dried) peptide with a liquid so it can be measured accurately. The maths is two short steps:
1 · Concentration
Peptide amount ÷ water volume. Example: 5 mg ÷ 2 mL = 2.5 mg/mL (2,500 mcg/mL).
2 · Volume to draw
Target amount ÷ concentration. Example: 250 mcg ÷ 2,500 mcg/mL = 0.1 mL = 10 units on a U-100 syringe.
A U-100 insulin syringe has 100 units per millilitre, so 1 unit = 0.01 mL. The calculator converts your draw volume into units automatically so you can measure to the exact graduation. Adding more bacteriostatic water lowers the concentration, which spreads each measurement over more units and improves precision.
Frequently asked questions
How do you calculate peptide reconstitution?
Divide the peptide amount in the vial by the volume of bacteriostatic water you add to get the concentration (for example, 5 mg in 2 mL = 2.5 mg/mL, or 2,500 mcg/mL). To find the volume to draw for a target amount, divide the target amount by that concentration. On a U-100 insulin syringe, multiply the millilitres by 100 to read it in units.
How much bacteriostatic water should I add to a peptide vial?
There is no single correct amount — more water simply makes each drawn unit contain less peptide, which improves measurement precision. A common choice is 1–3 mL for a small vial. Use this calculator to see the exact concentration and draw volume for the water amount you plan to use.
What is a unit on an insulin syringe?
A standard U-100 insulin syringe has 100 units per millilitre, so 1 unit = 0.01 mL. The calculator converts the draw volume into these units automatically so you can measure to the correct graduation.
How many doses are in one vial?
Divide the total amount in the vial by your target amount per draw. The calculator shows this as 'measurements per vial'.
What is bacteriostatic water?
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol, which inhibits bacterial growth so a reconstituted vial stays stable for multiple draws when refrigerated. It is used purely for laboratory reconstitution.
Is this peptide calculator free?
Yes — the calculator is completely free and runs instantly in your browser. No sign-up is required. It is provided for laboratory research and measurement only.