Pindrop

Bacteriostatic Water Calculator

Pick the dose you want and the number of units you would like to read on the syringe. This tells you how much bacteriostatic water to add so the math lands on a clean number.

mg
u

The tick you want to fill to.

mcg

Add this much water

4mL

Gives 2,500 mcg/mL, so 10u reads one dose.
Concentration
2,500mcg/mL
Water to add
4mL

What this calculator does

This is reconstitution run backwards. Instead of adding a set amount of water and finding out how many units your dose works out to, you choose the units you want to see on the syringe first, and the calculator finds the water volume that makes it true. It is the fastest way to avoid awkward draws like 6.5 or 13 units when a round 10 or 20 would be easier to read at the counter.

Enter the peptide amount in the vial, your intended dose, and the tick mark you want to land on. The result is the milliliters of bacteriostatic water to draw into the vial. Because the vial holds a fixed amount of peptide, adding more water lowers the concentration and pushes your draw toward a higher unit count; adding less does the opposite.

Reading the result

The main number is how much water to add. We also show the concentration you will end up with, so you can sanity-check it against the vial. Mix to that volume once, and every future dose reads the same clean number of units. If the water volume looks unusually large for a single vial, double-check your target so you are not over-diluting.

Common questions

How do I know how much bacteriostatic water to add?
Work backwards from the syringe. Decide the dose you want and the number of units you would like to read, and this calculator returns the water volume that makes it true. That way you avoid awkward draws and land on a round number every time.
Does adding more water change my dose?
No — the amount of peptide in the vial is fixed, so your dose stays the same. What changes is the concentration and therefore how many units that dose takes up on the syringe. More water means more units for the same dose.
Can I add water to a vial I already mixed?
You cannot un-mix a vial, and topping up an already-reconstituted vial changes the concentration in ways that are hard to track. Plan the water volume before you reconstitute. Use this calculator first, then mix once to that volume.
Is there a limit to how much water I can add?
Practically, yes. Small vials hold only so much liquid, and very dilute solutions mean large, hard-to-handle draws. If the calculated volume looks unusually large for one vial, lower your target unit count.

Pindrop is a calculation tool, not medical advice. Confirm your dose and protocol with a licensed healthcare provider.