Free Tool
Peptide Dosing Calculator
Enter your concentration and target dose to see the volume to draw and the units on an insulin syringe. A general estimate for clinician discussions — not medical advice.
Enter concentration + dose, then Calculate.
How The Math Works (Worked Example)
1. Concentration
A 5 mg vial + 2 mL BAC water = 2.5 mg/mL (5 ÷ 2).
2. Volume
A 250 mcg (0.25 mg) dose ÷ 2.5 mg/mL = 0.1 mL.
3. Units
0.1 mL × 100 = 10 units on a U-100 syringe.
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 do I calculate how many units to draw on an insulin syringe?
First find the volume in mL (target dose ÷ concentration in mg/mL), then convert to units. On a U-100 syringe, units = mL × 100; on a U-40 syringe, units = mL × 40. This calculator does both steps for you, but always confirm the final number with your 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.
How many units of semaglutide should I draw?
It depends entirely on your prescribed dose and the concentration of your specific vial, so there is no single answer. Enter your vial's mg/mL concentration and your prescribed dose into the calculator to estimate the units. Never set or change a semaglutide dose on your own — follow the exact instructions from your prescriber.
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.
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