Calculators
Reconstitution Calculator
Calculate how much to draw from your syringe based on your peptide vial, water volume and desired dose.
Draw to
— units
= — mL of — mcg/mL
More than one syringe — add more water or lower the dose.
- Doses per vial
- —
- Concentration
- — mcg/mL
Need supplies? Bac water · Syringes & swabs
For informational purposes only. Always verify calculations.
How the reconstitution maths works
Reconstitution is dissolving a lyophilised (freeze-dried) powder in a measured volume of bacteriostatic water so that a known amount of compound sits in every millilitre. Three numbers drive everything:
- Vial amount — the total milligrams of powder in the vial.
- Water added — the millilitres of bacteriostatic water you draw into the vial.
- Target amount — the micrograms or milligrams you want in a single draw.
Dividing vial amount by water added gives the concentration (mg/mL). Dividing your target amount by that concentration gives the volume to draw. The calculator then converts that volume into units on the syringe you selected (a 1mL insulin-style syringe is 100 units, so 0.1mL is 10 units).
Worked example
A 5mg vial reconstituted with 2mL of bacteriostatic water is 2.5mg/mL. A 250mcg draw is 0.25 ÷ 2.5 = 0.1mL, or 10 units on a 100-unit syringe.
Choosing how much water to add
More water means a larger, easier-to-measure draw for the same amount; less water means fewer draws fit in the vial before it runs out. Most people pick a volume that lands the usual draw between 10 and 50 units so small measuring errors matter less. Our 10mL, 30mL and 50mL vials use the same 0.9% benzyl alcohol solution, so the maths is identical whichever size you keep on the bench.
Once mixed, store the vial as described in our storage guide, and see how to open a vial if it is your first time working with a rubber-stoppered vial.
This tool is for laboratory and research use. It does not provide medical advice.