Reconstitution calculator
Enter your vial size, how much bacteriostatic water you added, and your dose. See exactly how many units to draw on a standard U-100 insulin syringe.
Reconstitution calculator
VIAL → UNITSmg
mL
mcg
Your conversion
—units on a U-100 syringe
Enter your values to see the math.
Educational only. Always follow your prescriber's dose and confirm the numbers with your pharmacist.
Only use medications prescribed to you, and follow your prescriber's and pharmacist's instructions. This tool does arithmetic; it can't tell you what dose is right for you.
How the math works
- Concentration = mg in vial ÷ mL of water. A 5 mg vial with 2 mL of water is 2.5 mg/mL (2,500 mcg/mL).
- Volume = dose ÷ concentration. A 250 mcg dose at 2,500 mcg/mL is 0.1 mL.
- Units = mL × 100 on a U-100 syringe. 0.1 mL is 10 units.
Quick reference: 5 mg vial
| Water added | Concentration | 250 mcg dose | 500 mcg dose |
|---|---|---|---|
| 1 mL | 5 mg/mL | 5 units | 10 units |
| 2 mL | 2.5 mg/mL | 10 units | 20 units |
| 2.5 mL | 2 mg/mL | 12.5 units | 25 units |
| 3 mL | 1.67 mg/mL | 15 units | 30 units |