Peptide reconstitution calculator
Vial size, water volume, target dose. The draw appears in syringe units, millilitres, and mg/mL — with a syringe drawn to match. Installs as an app and works offline.
The arithmetic, in one line
concentration (mg/mL) = vial mg ÷ water mL, then draw (mL) = dose mg ÷ concentration, then units = draw mL × 100. That last conversion holds because a U-100 insulin syringe is graduated so that 100 units is exactly 1 mL.
Where people get it wrong
The most common mistake is assuming more bacteriostatic water makes a dose weaker. It does not. Water changes only how much liquid carries the same amount of peptide. The second most common is reading units as millilitres — a 10-unit draw is 0.1 mL, not 10 mL.
Common questions
How do you calculate peptide reconstitution?
Divide the vial size in milligrams by the millilitres of bacteriostatic water you added — that is your concentration in mg/mL. Divide your target dose by that concentration to get the volume to draw. Multiply by 100 to convert millilitres into units on a standard insulin syringe.
How many units is 1 mL?
On a standard U-100 insulin syringe, 1 mL is 100 units. That conversion is fixed and is what makes it possible to state a peptide dose in units at all.
How much bacteriostatic water should I use?
There is no single right answer — water volume sets concentration, not dose. More water means a larger, easier-to-measure draw for the same amount of peptide. Many people pick a volume that puts their usual dose somewhere in the readable middle of the syringe.
Is there a peptide calculator app?
This site is one — it installs like an app and works offline. On iPhone, open the share menu and choose "Add to Home Screen." On Android or desktop Chrome, use the install prompt in the address bar. No app store, no signup, and once installed the calculator opens instantly even without a connection.
Does this calculator store what I enter?
No. The calculation runs entirely in your browser. Nothing is sent to a server, and nothing is saved.