Tools
Peptide Calculators
Convert what is printed on a vial, restate a quantity in the unit your syringe is actually marked in, work a dilution backwards, or divide a total you have already settled on. Every input starts empty. Nothing is ever suggested, defaulted, or pre-filled — you supply the numbers, the tool does the arithmetic and shows every step of it.
Arithmetic only, never a dose
5 available
Calculators
Reconstitution calculator
Convert a peptide vial's strength and your bacteriostatic water volume into insulin-syringe units for a dose you supply. Arithmetic only — not dosing advice.
Retatrutide calculator
Convert a retatrutide vial and your bacteriostatic water into syringe units for a dose you set. Read the supply and approval facts first — they matter more.
Microdosing split calculator
Divide a weekly total you have already decided on into smaller injections and see the syringe units for each. Your numbers only — no chart of amounts to copy.
Unit converter
Convert one quantity between micrograms, milligrams, milliliters and U-100 syringe units at a concentration you supply. Arithmetic only — never dosing advice.
Bacteriostatic water calculator
Work out how much bacteriostatic water to add to reach a concentration you have chosen, and what one syringe unit is worth once you get there.
Who this is for
Who these tools are for
Anyone who has already mixed a vial, already decided on a dose with a clinician or from a source they trust, and wants to check the syringe reading themselves rather than take someone else's word for the arithmetic. These tools are not a substitute for that decision — they start after it has been made.
Why trust the arithmetic
How the math works — and what it can't tell you
Almost everything on this page rests on one division and one multiplication: concentration is vial strength divided by water added, and syringe units are a quantity divided by that concentration, scaled to a standard U-100 syringe where 100 units hold 1 mL. The calculators differ in which of those variables you already have and which one you are solving for — every one of them shows the substituted working, not just the final number.
That straightforward division is also, provably, not exact. An FDA label's own published figures show that dividing by the diluent volume you added overstates concentration by more than 11% on at least one approved product, because dissolved powder takes up space of its own. Read the full worked example before you rely on either tool’s output as anything more precise than it is.
Glossary
Key terms
- Reconstitution
- Adding a liquid — usually bacteriostatic water — to a freeze-dried peptide powder to turn it into an injectable solution.
- Concentration (mg/mL)
- How much peptide is in each milliliter of the mixed solution — vial strength divided by water added.
- Syringe units (U-100)
- The markings on a standard insulin syringe, where 100 units equal 1 milliliter. A different syringe uses a different scale.
- Arithmetic only
- This site's term for what these tools do: convert numbers you supply, and never propose, default, or suggest a number of their own.
Every peptide these calculators are commonly used with has a different legal status — FDA-approved, compounding-restricted, or research-only. Each tool page states the status of the compounds it covers before you calculate anything, and links to the relevant evidence page where one exists. Start at the research index for the compound records themselves.