Already know your mixed concentration? Skip the vial math and convert a dose straight to syringe units. Need the concentration first? Use the full Reconstitution Calculator instead — it works out concentration from your vial size and BAC water, then does this same conversion for you.
Dose → units converter
A one-off calculation — nothing here is saved or sent anywhere.
How to Use This Calculator
Four inputs, no vial math required — useful once you already know what's in the syringe.
Find your concentrationCheck your vial label, or work it out with the Reconstitution Calculator if you mixed it yourself (peptide mg ÷ BAC water mL).
Enter the concentration and its unitMost peptide vials are labeled in mg/mL after mixing; some hormone products use mcg/mL — pick whichever matches your label.
Enter your target doseType the dose you're aiming for, in mcg or mg — whichever your protocol uses.
Pick your syringe typeU-100 insulin syringes are the most common for small subQ doses; U-40 and standard mL-marked syringes are also supported.
How the Math Works
This is unit conversion, not clinical guidance — the same arithmetic a pharmacist would use to translate a concentration and dose into a syringe reading.
Concentration → mcg/mL. Any mg/mL value is multiplied by 1,000 to get mcg/mL, since 1 mg = 1,000 mcg — the standard SI prefix relationship. SI unit definitions, BIPM.
Draw volume. Draw volume (mL) = dose (mcg) ÷ concentration (mcg/mL) — a straightforward division once both values share the same unit. Basic pharmaceutical calculation, standard nursing/pharmacy dosage-calculation method.
Units on the syringe. Syringe units = draw volume (mL) × the syringe's units-per-mL rating. A U-100 syringe reads 100 units per mL; U-40 reads 40 units per mL — these are fixed manufacturing standards, not variable by drug. U-100/U-40 insulin syringe graduation standards, ISO 7864.
Estimate only — not medical advice. This tool performs arithmetic only — it does not know what dose is appropriate for you, and individual response to any compound varies significantly. Confirm your concentration and target dose with your product label, prescriber, or pharmacist before drawing anything.
Frequently Asked Questions
What's the difference between mg and mcg?
A milligram (mg) equals 1,000 micrograms (mcg). Vial labels are usually in mg or mg/mL; individual peptide doses are often discussed in mcg because the amounts are so small. Mixing up the two is one of the most common (and most consequential) dosing mistakes — this calculator handles the conversion for you.
What does "units" mean on a syringe?
"Units" refers to the graduated markings on an insulin syringe, not a universal measure of drug amount. A U-100 syringe is calibrated so that 100 units equals 1 mL; a U-40 syringe is calibrated so 40 units equals 1 mL. The same volume reads as a different number of "units" depending on which syringe you're holding.
Can I use a U-100 syringe if my product is labeled U-40?
You can physically draw liquid into any syringe, but the unit markings will not correspond to the concentration your product expects — using the wrong syringe type is a well-documented source of significant dosing errors, particularly with insulin. Match your syringe type to your product, or convert carefully and double-check your math.
How do I find my concentration if I mixed the vial myself?
Concentration = total peptide in the vial (mg) ÷ bacteriostatic water added (mL). If you don't have both numbers handy, the full Reconstitution Calculator walks through that step and then performs this same mg-to-units conversion automatically.
Does this work for blends with more than one compound?
This tool assumes a single concentration value for the whole solution, which is correct for calculating total draw volume even with a blend — but it won't break out how much of each individual compound that draw contains. For a per-compound breakdown, use the Reconstitution Calculator, which has dedicated blend support.
Why is my syringe unit number not a round number?
Real-world doses and concentrations rarely divide evenly. A non-round number (like 23.7 units) is often accurate — but if your syringe can't be read that precisely, consider rounding to the nearest mark your syringe actually supports, or adjusting your concentration so doses land on cleaner numbers.
Is a mL-marked syringe the same as a U-100 syringe?
No. A standard mL-marked (e.g., tuberculin or 1-3 mL) syringe reads directly in mL or fractions of a mL, with no "units" concept at all. Selecting "1 unit = 1 mL" in this tool treats the syringe reading as mL directly, which is the correct way to model that syringe type.
Is this tool storing my numbers anywhere?
No — every calculation happens in your browser and nothing is saved, logged, or sent anywhere. If you want your dose history saved and tracked over time, that's what the full Peptide Plug app is for.
Can I trust this for a syringe with capacity smaller than my draw?
This calculator shows the syringe units needed but doesn't check syringe barrel capacity. If your draw volume is larger than your syringe can hold, you'll need a larger syringe or a more concentrated mix — the full Reconstitution Calculator includes a capacity warning and a live visual for exactly this check.
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