Peptide syringe calculator
Work out which barrel of a U-100 insulin syringe fits your draw in units, and how the tick marks differ for 0.3 mL, 0.5 mL, plus 1 mL.
Use this for reference only. The product label or your prescriber determines your dose; we only convert it to units.
- in 1 unit on a syringe marked U-100
- 0.01 mL
- amount in 100 units
- 1 mL
- contained in 1 mg
- mcg: 1,000
With a peptide syringe calculator, you can match the units of your dose to a U-100 syringe barrel that contains liquid and offers clear markings. Every U-100 syringe holds 100 units in 1 mL, so 1 unit always equals 0.01 mL of liquid. Your prescriber determines your dose; a smaller barrel simply spreads out the lines, which makes small draws easier to read.
The same dose and units on any U-100 syringe
Moving between a 0.3 mL U-100 syringe, a 0.5 mL one and a 1 mL one never changes the units you draw for your dose. With 1 mL of U-100 holding 100 units, a draw of 10 units always equals 0.1 mL of liquid on every U-100 barrel. You can compare all 3 barrels on insulin syringe sizes.
Finer marks on smaller barrels
Syringe sizes differ in two ways: the volume the barrel can hold and how close together the printed lines sit. Up to 30 units fit in a 0.3 mL syringe, marked every 1 unit; certain models add half-unit marks.
Up to 50 units fit in a 0.5 mL syringe, with a line for every 1 unit. When full, a 1 mL syringe holds 100 units, but its barrel has lines only every 2 units; our reading guide for insulin syringes shows where each line sits.
Pick a barrel that fits your draw on the peptide syringe calculator
The barrel must contain your full draw in 1 pull; a 30-unit syringe won't hold a 35-unit dose. Doses under 30 units suit a 0.3 mL barrel; doses of 30 to 50 units suit a 0.5 mL barrel, per Healthline's guide. For draws over 50 units, pick a 1 mL barrel; see advice on choosing a syringe for peptides for needle length and gauge details.
U-40 syringes are not covered
Our unit calculations apply only to standard U-100 human insulin syringes. Only 40 units fit in 1 mL of a veterinary U-40 syringe. If you use a U-100 unit number on the U-40 barrel, you get the wrong amount of medicine.
Frequently asked questions
Does the size of the syringe change the dose?
No, 15 units in a 0.3 mL U-100 syringe equal exactly 0.15 mL of liquid, just like 15 units in a 1 mL U-100 syringe. The plastic barrel changes in length and width only.
Which syringe do I need for 15 units?
You can measure 15 units with any U-100 insulin syringe, since 15 units is 0.15 mL. The 0.3 mL and 0.5 mL U-100 syringes are the simplest to work with, because each marks every 1 unit, so 15 gets a mark of its own.
Is a 1 mL syringe okay for small doses?
Yes, but only if it's a U-100 syringe; reading odd numbers takes more care. A 1 mL barrel has a mark every 2 units, so an odd draw such as 5 units or 15 units falls halfway between 2 printed lines.