This reverse reconstitution calculator works backward from a target syringe mark to tell you how much BAC water to add, so every dose lands on an easy-to-read line.
How to use the Reverse Reconstitution Calculator
- Enter the peptide in vial, or tap a preset.
- Enter the desired dose and choose mcg or mg.
- Enter the target units per dose, or tap a preset.
- Choose the syringe type.
- Read the result card. It updates as you type, and you can copy or share it.
About this calculator
Working backward from a syringe mark lets you pick a round number, like 10 units, and mix the vial so every dose lands exactly on it. This reduces reading errors, especially on small doses.
The calculator assumes the powder adds no meaningful volume, which holds for typical peptide amounts under about 20 mg.
Frequently asked questions
What target units should I choose?
Pick a mark that is easy to read on your syringe and keeps the total water between about 1 and 3 mL for a standard vial. 10 or 20 units on a U-100 syringe are common choices.
Can I add water in two steps?
Yes, but the concentration is only correct after all the water is in. Recalculate if you change the total volume.
Sources
- ISO 8537: Sterile single-use syringes for insulin. International Organization for Standardization.
- General Chapter <797> Pharmaceutical Compounding: Sterile Preparations. U.S. Pharmacopeia.
Related calculators
- Peptide Reconstitution Calculator: This peptide reconstitution calculator shows how many units to draw after mixing a peptide vial with bacteriostatic (BAC) water. Enter the amount on the vial label, the water you added, and your dose.
- Insulin Syringe Units Calculator: This insulin syringe units calculator converts any dose and concentration into the units and milliliters to draw, with a syringe diagram showing the fill line.
- Peptide Concentration Calculator: This peptide concentration calculator shows how strong your solution is after reconstitution, in mg/mL, mcg/mL, and mcg per insulin syringe unit.
- Doses per Vial Calculator: This doses per vial calculator divides the amount in your vial by your dose to show how many full doses you get and what is left over.
Medical disclaimer. This calculator is for educational purposes only and is not medical advice. Results are mathematical estimates based on the values you enter. Many peptides listed here are not approved by the FDA for human use. Confirm every dose with a licensed healthcare provider or your approved study protocol, and follow the product label.
