mg to Syringe Units Calculator

From milligrams to unit marks

Insulin-style syringes aren't marked in mL -- they're marked in "units", where a U-100 syringe measures 100 units per mL, a U-40 syringe measures 40 units per mL, and so on. Getting from a prescribed mg dose to a unit mark takes three steps:

1. Work out the vial's concentration: vial amount (mg) ÷ diluent volume (mL)
2. Work out the dose volume: prescribed dose (mg) ÷ concentration (mg/mL)
3. Convert to units: dose volume (mL) × units-per-mL of your syringe

Worked example

A 2 mg vial reconstituted with 2 mL, prescribed dose 0.2 mg, on a U-100 syringe:

1. Concentration: 2 mg ÷ 2 mL = 1 mg/mL
2. Dose volume: 0.2 mg ÷ 1 mg/mL = 0.2 mL
3. Syringe units: 0.2 mL × 100 = 20 units

When the mark falls in between

Not every result lands cleanly on a graduation line. A syringe with 2-unit gradations can't precisely measure 21 units, for example -- you'd be estimating between two marks. PeptOnyx Calculator checks this automatically and warns you when a result doesn't land on an exact mark, so you can round carefully or pick a different syringe size instead of guessing.