Tools

Reconstitution calculator

Enter what is in the vial and what you are adding to it. You get the concentration, the unit to draw to on an insulin barrel, and how many draws the vial yields. Nothing is sent anywhere — the arithmetic runs in your browser.

Your vial

Common vial sizes
Common volumes

Standard vials take up to about 3 mL.

Your draw

Amount unit
Common doses

Work backwards

Pick the unit you want to draw to and this returns the water volume that puts your dose there.

Add 4 mL

Results

Draw to

5units

0.05 mL on a U-100 · 1 mL barrel

050100

Concentration

5 mg/mL

5,000 mcg per mL

Per unit

50 mcg

One unit on this barrel

Draws per vial

40

10,000 mcg total in the vial

Per draw

250 mcg

0.25 mg

  • Units are volume, not potency — one unit on this barrel is 1/100 mL of whatever is in the vial, so every number here moves the moment the water volume does.

Method

Three lines of arithmetic

  1. Step 1

    Concentration

    mg in vial ÷ mL of water = mg per mL

    10 mg into 2 mL is 5 mg/mL — 5,000 mcg in every millilitre.

  2. Step 2

    Value of one unit

    mcg per mL ÷ units per mL = mcg per unit

    At 5,000 mcg/mL, a U-100 barrel carries 50 mcg behind each of its 100 units.

  3. Step 3

    The draw

    amount per draw ÷ mcg per unit = units

    250 mcg at 50 mcg per unit is 5 units, which is 0.05 mL.

Quick conversions

1 mg
= 1,000 mcg
1 mL
= 100 units (U-100)
1 unit
= 0.01 mL (U-100)
1 mL
= 40 units (U-40)

Questions

Reconstitution, answered

For research use only · Not for human consumption