How much water do I need?
There is no unique water volume for a given vial mass alone. A 10 mg vial can produce several concentrations depending on final volume. You need another condition: a target concentration, or a known target amount and the volume you want that amount to occupy.
The calculator returns final solution volume. Water-added volume is only an approximation to that result when powder displacement and other volume changes are neglected. It does not select a diluent or check your container capacity.
Two ways to solve for volume
The target U-100 mark is a volume reference: 10 units corresponds to 0.1 mL on a U-100 scale. A number of units does not identify a mass without the concentration.
Target concentration: V (mL) = mass (mg) ÷ concentration (mg/mL)
Target U-100 mark: V (mL) = mass (mg) × 1,000 × [units ÷ 100] ÷ target (mcg)A worked concentration example
For a mathematical example of 10 mg and a target concentration of 5 mg/mL, the final solution volume is 2 mL. These example conditions are not a recommendation for any compound.
Questions about this calculator
Can I calculate water for a 20 mg vial with no other information?
No. Supply a known target concentration, or a target amount and U-100 mark. Vial mass by itself is insufficient.
Does the result mean this water volume will fit in my vial?
No. The calculator does not know the physical vial capacity. Verify the container separately.