The Basics
Insulin syringes are marked in units, not milliliters. On the standard U-100 scale, 100 units equals 1 mL. The markings make it easy to measure small volumes precisely.
Syringe Sizes
Insulin syringes come in three common sizes:
- 1 mL (100 units): Major marks every 10 units, minor marks every 2 units. Best for doses between 10 and 100 units.
- 0.5 mL (50 units): Major marks every 5 units, minor marks every 1 unit. Better resolution for smaller doses.
- 0.3 mL (30 units): Major marks every 5 units, minor marks every half-unit. Best for micro-dosing.
How to Read the Level
Hold the syringe at eye level with the needle pointing up. Read the measurement from the top edge of the plunger (the flat rubber surface), not from the tip of the needle or the bottom of the plunger.
Drawing a Dose
- Pull the plunger back to the line matching your dose
- Insert the needle into the vial (inverted)
- Push the air in, then pull back past your target mark
- Tap out air bubbles, then push the plunger back to the exact line
Quick Reference
| Units | mL |
|---|---|
| 5 | 0.05 |
| 10 | 0.10 |
| 25 | 0.25 |
| 50 | 0.50 |
| 100 | 1.00 |