Peptide reconstitution calculator
Three modes: the units to draw for a dose, what a mark you already drew actually delivered, and how much bacteriostatic water makes your dose land on a round number. Free, no account, and nothing you type is sent anywhere.
I want this dose — how far do I fill?
Draw to 5 units
50 µL on a U-100 barrel
- Concentration
- 5 mg/mL
- One unit is
- 0.05 mg
- Doses in the vial
- 40
Free, no signup. This runs entirely in your browser — nothing you type here is sent anywhere or stored, by us or by anyone else.
How the arithmetic works
Concentration is the powder divided by the water: 10 mg ÷ 2 mL = 5 mg/mL. Everything else follows from it.
A syringe’s markings are a volume scale, not a dose scale. A U-100 barrel has 100 marks per mL, so one mark is 10 µL. On a U-40 barrel one mark is 25 µL — two and a half times as much. Reading a U-100 number off a U-40 barrel is the most dangerous mistake available here, which is why the barrel above is drawn with its own numbering rather than a generic 0–50.
Your dose divided by the concentration gives a volume, and that volume rarely lands exactly on a mark. This calculator snaps to the nearest one you can actually read and tells you what that mark delivers, rather than pretending you drew a figure no barrel displays.
Doing this for a whole stack?
PepStepper keeps the concentration with the vial, converts every dose as you log it, tracks injection sites across compounds, and tells you whether the pep or its fridge life runs out first.