Peptide pen calculator

Divide the vial mass by the water volume to get the concentration in mg/ml. Divide your dose by that concentration to get the volume of one injection in ml. On a U-100 insulin syringe every 0.01 ml is one unit, so multiply that volume by 100. The calculator does exactly this and shows both steps.

More water gives larger, easier-to-measure draws; less water gives smaller draws that fit smaller barrels. 2 ml is the most common choice for a 5–10 mg vial. Pick the amount whose draw lands comfortably on your syringe's scale — the fit line under the result says when a draw is too fine to measure or too big for the barrel.

Yes. Switch the device to Pen and the calculator speaks pen: you set the dial's click size (1 unit on most reusable cartridge pens, ½ unit on half-unit models) and the pen's maximum per injection (30, 60, or 80 units). The result is the number to dial in the dose window, the calculator warns when a dose lands between clicks, and when a dose exceeds the pen's per-injection maximum it shows the split — or the water volume that gets it back to one injection.

U-100 is the standard insulin syringe: 100 units per millilitre. It is what the units on the barrel are calibrated to. If you have a U-40 or U-500 barrel (rare, mostly veterinary), the unit markings mean something different and this calculator's unit readout will not apply.

Any lyophilized peptide — the math is the same regardless of the compound. The picker lists 74 of the most common ones (GLP-1s like semaglutide, tirzepatide and retatrutide, growth-hormone peptides, healing peptides like BPC-157 and TB-500, and more) purely to label the calculation. Selecting one never changes your numbers.

No. It performs arithmetic on numbers you enter. It does not recommend a dose, a compound, or a protocol, and it never pre-fills a dose for you. For medical decisions, consult a qualified healthcare professional.