Syringe Unit Converter
Convert between units on an insulin syringe, volume in millilitres, and the actual amount in mcg or mg. Handles both U-100 and U-40 scales — the distinction that causes the most expensive mistakes.
Equivalents
- Volume
- 0.1 mL
- Amount
- 250 mcg
- Per 1 unit
- 25 mcg
How the conversion works
Insulin syringes are marked in units rather than millilitres, and a unit is a fixed fraction of a millilitre — but which fraction depends on the scale the syringe was made for.
- U-100 is calibrated for 100 units per mL, so 1 unit = 0.01 mL. This is the standard human insulin syringe and what almost every peptide guide assumes.
- U-40 is calibrated for 40 units per mL, so 1 unit = 0.025 mL. It is mostly veterinary.
Barrel size does not change this. A 0.3 mL, 0.5 mL, and 1 mL U-100 syringe all read the same at the 10-unit mark; they just hold 30, 50, and 100 units in total.
Units and millilitres describe volume only. To reach an actual amount in mcg or mg you also need the concentration, which is why that field feeds the amount row.
The formulas
mL = units ÷ scale (scale is 100 or 40)
amount = mL × concentration
On a U-100 syringe at 2.5 mg/mL: 10 units = 0.1 mL = 250 mcg.
Frequently asked questions
How many mL is 10 units?
On a U-100 syringe, 10 units is 0.1 mL. On a U-40 syringe the same 10 marks are 0.25 mL — two and a half times more liquid.
Is a 0.5 mL syringe the same as U-50?
No, and this is a common mix-up. "U-50" is not a standard concentration. A 0.5 mL insulin syringe is normally a U-100 syringe that holds 50 units. The markings are U-100 markings; only the capacity is smaller.
Do I need the concentration?
Only to convert to or from an amount in mcg or mg. Units and mL are pure volume and convert without it.
What if my syringe is marked in mL?
Then use the volume row directly and ignore units. Tuberculin and standard syringes are marked in mL and need no unit conversion at all.
Keep the numbers with the routine
PepTrack saves concentration, unit counts, and vial details alongside each entry, so the math stops being something you redo every week. Free on iPhone, no account required.
Download on the App Store