BAC Water Calculator: Reconstitution & Syringe Units
By James Li, Lead Editor · Updated · Reviewed
Quick answer
Enter three numbers for bacteriostatic water, which are the milligrams on the vial, the milliliters of water you added, and the amount you want to measure in mcg or mg, and the calculator divides milligrams by milliliters, converts your amount into the same units, and shows the mark on a U-100 syringe (a 30-unit, 50-unit, or 100-unit barrel).
If you already know the mark you want, switch to Units to water and it solves for the liquid volume that lands your amount on that mark, while a blend adds each peptide's milligrams first, and the round sample later on the page is there so you can follow the steps rather than as a dose.
Blends
Optional. Extra peptides are added to the vial total.
Waiting on Input
5 mg vial, 2 mL water, 250 mcg. Example only, not a dose.
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Illustrative arithmetic only, not a recommendation. The result for BAC water uses only the numbers you type.
How does the BAC water calculator work?
Three entries run the forward calculation for bacteriostatic water, which are the milligrams on the vial, the milliliters of water added, and the amount you want to measure.
The calculator divides milligrams by milliliters to get the concentration, converts your amount into micrograms, divides to get milliliters, and multiplies by 100 for a U-100 mark, and you switch to Units to water when you already know the mark and want the water volume instead.
What inputs does the calculator need?
Dose to units needs the vial milligrams, the water milliliters, and the amount to measure in mcg or mg, and one milligram is entered as 1,000 micrograms if you leave the unit on mcg.
Units to water needs the vial amount, the amount you want to measure, and the syringe mark you want to hit, while a blend is optional because each extra peptide adds its own milligrams to the vial total before the division, and dead space, if you set it, adds that many milliliters to the draw.
Worked example with sample numbers
Walk the sample in order by dividing vial milligrams by water milliliters, converting the amount you want to measure into micrograms, dividing by the concentration in mcg/mL, and then multiplying the milliliters by 100 for a U-100 mark.
These are sample numbers only and not a dose: 10 mg in 2 mL is 5 mg/mL, or 5,000 mcg/mL, and measuring 500 mcg from that mix is 0.1 mL, which is 10 units on a U-100 syringe.
How do 100-unit, 50-unit, and 30-unit U-100 barrels differ?
A U-100 syringe marks 100 units per milliliter, so each unit is 0.01 mL, and that definition does not change with the barrel.
A 30-unit barrel holds 0.3 mL, a 50-unit barrel holds 0.5 mL, and a 100-unit barrel holds 1 mL, so if the calculated draw is larger than the barrel you selected it does not fit in one syringe and the calculator says so.
Common calculation mistakes
Three mistakes account for most wrong marks.
People read the syringe number as milligrams when it is a volume, forget that 1 mg is 1,000 mcg which makes the draw a thousand times off, or type a water volume they meant to add but did not, and dead space is a fourth, smaller one because liquid left in the needle is not in the barrel mark unless you add it.
Unit math
Illustrative arithmetic only. Not a dose. Barrel columns use a U-100 scale, 100 units per mL.
| Vial mg | Water mL | mg/mL | mcg/mL | mcg in 10 units |
|---|---|---|---|---|
| 10 | 2 | 5 | 5,000 | 500 |
| 5 | 1 | 5 | 5,000 | 500 |
| mL | 1 mL barrel (U-100 scale) | 0.5 mL barrel (U-100 scale) | 0.3 mL barrel (U-100 scale) |
|---|---|---|---|
| 0.05 | 5 | 5 | 5 |
| 0.1 | 10 | 10 | 10 |
| 0.25 | 25 | 25 | 25 |
| 0.5 | 50 | 50 | 50 (past barrel) |
| 1 | 100 | 100 (past barrel) | 100 (past barrel) |
FAQ
What is BAC water for peptides?
There is no single volume of bacteriostatic water for bacteriostatic water, and more water lowers the concentration, so switch the calculator to Units to water, enter the vial milligrams, the amount you want to measure, and the unit mark you want, and the result is the milliliters of water.
Is reconstitution solution the same as bacteriostatic water?
Not always, because reconstitution solution only means the liquid used to dissolve a powder, bacteriostatic water is one kind of that liquid since it is sterile water plus a preservative, and sterile water without a preservative is another, so the label names which one you have.
Is BAC water FDA approved?
Bacteriostatic water is sold as a sterile diluent, so match your bottle to its own label.
How do I use the BAC water calculator?
Type the milligrams on the vial, the milliliters of water you added, and the amount you want to measure, and the syringe mark updates in the calculator.
What is BAC water?
BAC water is bacteriostatic water, which is sterile water with a preservative used to dissolve a dry vial, and the volume you add is what sets the concentration.
Sources
- Drugs@FDA, FDA
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