Free arithmetic tool
Dose-to-Volume Converter
Convert a labeled concentration and clinician-provided dose into volume and syringe-scale math. This tool does not choose or verify a medication or dose.
Enter the label values and clinician-provided dose to see the arithmetic conversion.
How the conversion works
1. Concentration
Vial amount ÷ labeled diluent volume = mg/mL.
2. Volume
Clinician-provided dose ÷ concentration = volume in mL.
3. Units
Volume × the printed syringe scale = the mathematical mark.
On a U-100 insulin syringe, the scale reads 100 units per mL, so units = mL × 100. That means 1 mL is 100 units and 0.1 mL is 10 units. A U-40 syringe reads 40 units per mL instead (units = mL × 40), so the identical 0.1 mL would read as just 4 units. The volume never changes — only the number printed on the barrel does — so always match the syringe setting above to the syringe you are actually holding.
Educational reference only — not a recommendation to use, inject, start, stop, or change any substance, dose, or medication. Always follow your prescriber's guidance.
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Frequently asked questions
How is a dose converted to an insulin-syringe scale?
First find the volume in mL (clinician-provided dose ÷ labeled concentration in mg/mL), then convert that volume to the scale printed on the syringe. On a U-100 scale, the mathematical mark is mL × 100; on U-40 it is mL × 40. Always confirm the inputs and final mark with a prescriber or pharmacist.
What does U-100 mean on an insulin syringe?
U-100 means the syringe is graduated for insulin at 100 units per mL, so 1 mL equals 100 units and 0.1 mL equals 10 units. U-40 syringes read 40 units per mL instead. Using the wrong syringe scale changes the units you draw, so match the calculator's syringe setting to the syringe in your hand.
How do I convert mcg to units for peptide dosing?
Convert the dose from micrograms to milligrams first (1,000 mcg = 1 mg), then divide by the concentration in mg/mL to get the volume, and multiply by your syringe's units-per-mL. For example, a 250 mcg dose is 0.25 mg; at 2.5 mg/mL that is 0.1 mL, which is 10 units on a U-100 syringe. This is a general estimate — verify with your clinician.
Why is there no single syringe mark for semaglutide?
The mathematical mark depends on both the prescribed dose and the concentration of the specific product, so there is no universal number. Use only the concentration and dose from your label or written instructions, and confirm the result with a prescriber or pharmacist.
Why does the same dose give a different number of units on different syringes?
The volume in mL stays the same, but units depend on the syringe's scale. The identical 0.1 mL is 10 units on a U-100 syringe and 4 units on a U-40 syringe. Always read the units against the syringe you are actually using.
Is this peptide dosing calculator medical advice?
No. It is an educational arithmetic tool that gives a general estimate of volume and syringe units from numbers you enter. It does not recommend any dose, drug, or treatment. Always follow the directions of your prescriber and pharmacist.