How to use this calculator#
- Enter your peptide. Pick single peptide or a blend, then type how much is in the vial (check the label — usually in mg). For blends, add each component or quick-fill a known stack.
- Set your BAC water. Enter how many milliliters of bacteriostatic water you're adding. Not sure? It auto-fills a sensible default you can override.
- Enter your target dose. Type the research dose you want (mcg, mg, IU, or mL). The calculator returns the exact syringe units to draw, the solution concentration, and how many full doses the vial yields — with a syringe diagram showing the fill.
For the full walkthrough — what BAC water is, how to mix without degrading the peptide, and storage — see the complete guide to reconstituting peptides.
How the reconstitution math works#
Two simple formulas drive everything:
Concentration (mg/mL) = peptide (mg) ÷ BAC water (mL) Units to draw = desired dose (mcg) ÷ (concentration × 10)
A 1 mL insulin syringe holds 100 units, so 1 unit = 0.01 mL and mcg per unit = concentration × 10.
Example: a 10 mg vial in 2 mL of BAC water = 5 mg/mL = 50 mcg per unit. A 250 mcg dose = 250 ÷ 50 = 5 units.
BAC water & concentration reference chart#
There's no single "right" amount of water — more water gives a lower concentration and a larger, easier draw. Common vial sizes:
| Vial size | BAC water | Concentration | Per syringe unit | 250 mcg dose | 500 mcg dose |
|---|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 50 mcg | 5 units | 10 units |
| 5 mg | 2 mL | 2.5 mg/mL | 25 mcg | 10 units | 20 units |
| 10 mg | 1 mL | 10 mg/mL | 100 mcg | 2.5 units | 5 units |
| 10 mg | 2 mL | 5 mg/mL | 50 mcg | 5 units | 10 units |
| 10 mg | 3 mL | 3.33 mg/mL | 33 mcg | 7.5 units | 15 units |
| 15 mg | 3 mL | 5 mg/mL | 50 mcg | 5 units | 10 units |
| 20 mg | 2 mL | 10 mg/mL | 100 mcg | 2.5 units | 5 units |
| 30 mg | 3 mL | 10 mg/mL | 100 mcg | 2.5 units | 5 units |
Frequently asked questions
How does a peptide reconstitution calculator work?
You enter the milligrams in your vial and the milliliters of bacteriostatic water you're adding; the calculator divides mg by mL to get the concentration, then converts your target dose into syringe units (1 mL = 100 units). It removes the manual arithmetic and the unit-conversion errors that cause mis-draws.
How much BAC water should I add?
Enough to land on an easy-to-draw concentration. For a 10 mg vial, 1–3 mL is typical. Less water = smaller, more concentrated draw; more water = larger, easier-to-measure draw. The calculator suggests a default and the chart above shows the trade-offs.
Can it calculate doses for peptide blends?
Yes. Switch to "Blend" mode and enter each component (or quick-fill a known stack like BPC-157 + TB-500). The tool tracks each peptide's concentration separately and shows how much of each you get per dose — something most calculators can't do.
What does "units" mean on the result?
Units are the markings on a standard 1 mL insulin syringe (100 units = 1 mL). "Draw to 5 units" means pull the plunger to the 5 mark.
Is bacteriostatic water the same as sterile water?
No. BAC water contains 0.9% benzyl alcohol as a preservative, so a vial stays usable for weeks; plain sterile water has no preservative and is single-use. See the full guide for details.
Where to buy peptides#
Once you know your dose, compare live vendor pricing. Peptide Supply Co. is our top-rated source; we track current prices across vetted vendors:
See the full where to buy BPC-157 and where to buy tirzepatide guides for vendor reviews and COA details.