Free tool

Syringe units converter

Your mixed vial strength and your desired dose — we'll give you the exact units and mL to draw on a U-100 insulin syringe.

Vial strength after mixing
mg/mL

On a U-100 insulin syringe, 100 units = 1 mL. This tool converts volume — it does not suggest what dose to take.

Draw to
—
units on your syringe
Volume—
Concentration—

Stack keeps this running for you

The app does this math on every vial you mix, and remembers the concentration so you never have to re-enter it.

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How the math works

Volume per dose = your dose ÷ the concentration. A 250 mcg (0.25 mg) dose at 2.5 mg/mL is 0.1 mL.

Syringe units = volume × 100, because a U-100 syringe reads 100 units to the mL by definition. 0.1 mL = 10 units, on any U-100 syringe regardless of its barrel size — the barrel only limits how much you can draw at once.

Not medical advice. This calculator converts volumes. It does not recommend a compound or a dose — your dose comes from your clinician or your own research.