What the calculator does
For an already mixed vial, start with your target dose or a whole number of equal injections. Then enter the peptide amount in the full vial and how much bacteriostatic water you added. The calculator uses that water amount as an estimate of the final mixed volume. The calculator shows the amount and liquid volume per injection, with the corresponding U-100 syringe units. If your label already gives a concentration, use it directly with your target dose instead of estimating from water added.
To plan a mix, enter your target dose or injection count, vial amount, and syringe line spacing. Compare water amounts and their estimated draws, then select an option or enter your own water amount. “Easy to measure” identifies a measurement preference, not product compatibility or a recommended mixture. The optional “Choose a syringe draw instead” mode works backward to a final mixed volume, which is not automatically water to add. The formula guide explains the calculations.
The tool does not choose a medically appropriate dose, assess a product’s quality, or recommend a treatment, schedule, or mixture. It does not require prescription status.
How results are handled
Mass fields start in mg, with mcg available. The injection syringe starts at U-100, 1 mL (100 units), and the mixing syringe starts at 3 mL; both capacities are editable. Mixing syringe capacity does not establish vial capacity or the water amount. Check these visible settings against your inputs and syringe. Line spacing starts at 1 unit for the insulin syringe and 0.1 mL for the mixing syringe. Both are editable; check them against the printed lines. Capacity and marking interval are checked separately for each syringe. A supplied “Maximum water for this vial” filters water options; an omitted limit remains unknown.
The calculation uses exact fractions internally after converting mass to mg. For selected-water and water-added paths, the concentration and draw remain estimates: exact arithmetic does not establish the actual finished volume or concentration. No universal powder-volume correction is applied; the formula guide explains this assumption. Recurring decimal results are labeled as approximate, with exact fractions shown for the relevant quantities. Syringe-line checks use the exact result and never round to a nearby line. Across mixing and draw calculations, results between printed lines remain visible with a measurement note; they are not presented as printed markings. Water comparisons favor draws on printed lines, while retaining fractional draws. Only aligned draws receive the “Easy to measure” label. Invalid entries, amounts exceeding known vial content, and draws exceeding syringe capacity are treated as errors. Editing inputs or changing modes clears the previous result.
Equal-injection calculations divide a full vial, not what remains in a partly used vial. Full-injection counts and leftover peptide are theoretical quantities before liquid left in the vial or syringe; they do not guarantee the number of injections you can extract. The calculator supports single-ingredient vials and cannot identify or verify ingredient composition.
Software checks address arithmetic and interface behavior. They cannot verify your label, syringe, or entered values, and they do not establish clinical validation. This site has not been clinically reviewed or certified.
Why units are explicit
The FDA has reported dosing errors involving confusion between mg, mL, and syringe units in its compounded semaglutide alert. That supports making these distinctions visible across this general calculator; it does not establish an appropriate dose for any product.
Our notation also follows the FDA’s strength-conversion guidance on explicit units, “mcg,” and leading zeros. These sources explain measurement concerns; they do not endorse this website.
Added liquid and final solution volume need not match: the FETROJA label, section 2.3, explicitly distinguishes them. This source supports disclosing the water-based estimate; it supplies no correction factor or preparation instructions for other products.
The bacteriostatic water label directs users to the drug manufacturer’s instructions for diluent choice and dilution volume. Our measurement comparison cannot supply those product-specific instructions.