Peptide calculator and syringe units converter
Type what's in your vial and the water you added, or the strength on a pre-mixed vial's label, then your dose. You'll see how many units to draw on a U-100 insulin syringe.
Units to draw = dose ÷ strength × 100
This does arithmetic on the numbers you type. It doesn't suggest a dose. Check the result with your prescriber or pharmacist.
Draw to
–units
Fill in the vial, water and dose
–
Strength
–
Syringe fill
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Doses per vial
Worked example
A 10 mg vial mixed with 2 mL of water holds 5 mg in every mL. 1 mg ÷ 5 mg/mL = 0.2 mL, and 0.2 mL is 20 units on a U-100 syringe.
A pre-mixed vial labelled 5 mg/mL skips the first step: 30 units is 0.3 mL, and 0.3 mL × 5 mg/mL = 1.5 mg.
IU works the same way. A 5,000 IU vial with 1 mL of water holds 5,000 IU per mL, so 250 IU is 0.05 mL, or 5 units.
How the math works
Strength is the amount in the vial divided by the water you added. A pre-mixed vial prints it on the label.
mL = dose ÷ strength, and units = mL × 100, because a U-100 syringe holds 100 units in 1 mL. The 0.3 mL and 0.5 mL syringes use the same scale and stop at 30 and 50 units.
It's the same code the PepBloom app runs, and it runs in your browser. Nothing you type leaves this page.
Questions
How are syringe units calculated?
Divide your dose by the vial's strength to get mL, then multiply by 100. The strength is the amount in the vial divided by the water you added, and the 100 is because a U-100 syringe holds 100 units in 1 mL.
What does mcg per unit mean?
It's how much is in each unit you draw. One unit is 0.01 mL, so divide the strength in mcg per mL by 100. A 10 mg vial mixed with 2 mL of water holds 5 mg, or 5,000 mcg, per mL, which is 50 mcg in every unit.
Does syringe size change the concentration?
The concentration comes from the vial and the water you added, so it stays the same in any syringe. The 0.3, 0.5 and 1 mL U-100 syringes share one scale of 100 units per mL. The smaller ones just stop at 30 or 50 units.
What's the difference between mg and units?
A mg is an amount of medicine. Units on an insulin syringe measure volume, not medicine: one unit is 0.01 mL. So the same 20 units can hold different amounts in two vials. Mixing the two up is one of the dosing errors FDA has warned about.
Sources
Related
Tirzepatide units to mg · Semaglutide units to mg · Units to mL · Vial run-out date
Track every dose with these units in PepBloom
Save your vial once and every dose you log shows its units.