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Reverse reconstitution calculator

Already mixed your vial and drew some units? Work backwards — enter the vial, the water you added, and the units on the syringe to see exactly what dose that is.

Your vial and draw

Example numbers
That draw is 500 mcg, 0.5 mg. Concentration 2,500 mcg per mL, 10 doses per vial.

That draw is

500mcg(0.5 mg)

0.3 mL insulin syringe · 30 units
Concentration
2,500 mcg/mL
Doses per vial
10

Working reconstitution backwards

Reconstitution usually goes from dose to units: you know the dose you want and work out how many units to draw. The reverse is just as useful — you've already mixed a vial and want to know what a given draw is. The math runs the other way: dose (mcg) = units ÷ 100 × concentration (mcg/mL), where concentration = vial mg × 1000 ÷ water mL.

Example: in a 5 mg vial mixed with 2 mL of water (2,500 mcg/mL), a 20-unit draw on a U-100 syringe is 500 mcg (0.5 mg), and the vial holds 10 doses.

Going the usual direction instead? Use the reconstitution calculator to turn a target dose into the units to draw, or mix the vial and draw it in the 3D Reconstitution Lab.

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