Units to millilitres
This conversion is fixed and needs nothing else. A U-100 syringe is graduated at 100 units per millilitre, so every unit is one hundredth of a millilitre, regardless of what the syringe contains.
U-100 insulin syringe: units to millilitres.
| Units | Millilitres (mL) |
|---|---|
| 5 units | 0.05 mL |
| 10 units | 0.10 mL |
| 20 units | 0.20 mL |
| 25 units | 0.25 mL |
| 30 units | 0.30 mL |
| 50 units | 0.50 mL |
| 100 units | 1.00 mL |
The three common barrel sizes
All three are U-100, and the scale is identical. What differs is how much of it is printed on the barrel, and therefore how finely it is graduated.
| Barrel | Total capacity | Typical graduation | Reads well for |
|---|---|---|---|
| 0.3 mL | 30 units | 1 unit, often ½ unit | Small draws |
| 0.5 mL | 50 units | 1 unit | Mid-range draws |
| 1 mL | 100 units | 2 units | Larger draws |
Micrograms to units
This conversion is not fixed, because micrograms measure peptide and units measure volume. The bridge between them is the concentration of the reconstituted vial.
- Convert the dose to mg: mcg ÷ 1,000.
- Convert to volume: mg ÷ concentration in mg/mL.
- Convert to units: mL × 100.
Units for a range of doses, from a 5 mg vial reconstituted with 2 mL of bacteriostatic water (2.5 mg/mL).
| Dose | Volume | U-100 units |
|---|---|---|
| 100 mcg | 0.04 mL | 4 units |
| 250 mcg | 0.10 mL | 10 units |
| 500 mcg | 0.20 mL | 20 units |
| 750 mcg | 0.30 mL | 30 units |
| 1,000 mcg | 0.40 mL | 40 units |
That table is only valid at 2.5 mg/mL. At any other concentration every row changes, which is exactly why the reconstitution calculator asks for the vial strength and water volume rather than assuming them.
