Reconstitution Concentration Calculator
Enter the mass of lyophilized compound in a vial and the volume of bacteriostatic water added. This tool returns the resulting solution concentration — and, optionally, the volume of solution that contains a given amount. It is arithmetic only: it does not recommend how much solvent to add, how much solution to prepare, or how a material should be used, and it is not a protocol.
Calculator
Research use only. For laboratory research use only. Not for human consumption. This tool is a laboratory measurement aid for reconstituted research solutions — not for human administration. It makes no dose recommendation, provides no protocol, and gives no guidance on how much of any material to use.
How the numbers are computed
Concentration is mass divided by volume. If a vial holds P mg of compound and V mL of solvent is added, the solution concentration is:
concentration (mg/mL) = P ÷ V
The volume of that solution containing a chosen amount T is that amount divided by the concentration (T ÷ concentration). The optional U-100 line simply expresses that volume in syringe graduations: a U-100 barrel is graduated so 1.00 mL = 100 graduations (0.01 mL each). It is a reading of volume on a graduated barrel, nothing more.
Worked example: a 10 mg vial reconstituted with2 mL gives 5 mg/mL. A volume containing 250 mcg is 0.05 mL— 5.0 graduations on a U-100 barrel.
For a fuller explanation of reconstitution as a laboratory procedure — solvents, sterility, storage, and this same math in context — see the companion guide:Reconstitution for research →
Questions about the math
How is solution concentration calculated?
Concentration is mass divided by volume. When a vial of lyophilized compound is dissolved in a measured volume of solvent, the concentration equals the mass in the vial divided by the volume of solvent added — milligrams divided by millilitres gives a result in mg/mL. The calculator performs this arithmetic and also reports the same value in mcg/mL. It reports the strength a given pairing produces; it does not suggest what mass or volume to use.
Why is concentration expressed in mg/mL and mcg/mL?
Milligrams per millilitre (mg/mL) and micrograms per millilitre (mcg/mL) are the standard units for the strength of a reconstituted solution — they state how much compound is present in each millilitre. The two are the same quantity at different scales: one mg/mL equals 1,000 mcg/mL. Reporting both lets a small concentration be read without a string of leading zeros.
What is a U-100 syringe graduation?
A U-100 syringe barrel is graduated so that one millilitre spans 100 evenly spaced marks, making each graduation 0.01 mL. A graduation is simply a division on the barrel's printed scale — a unit for reading a volume off the barrel, nothing more. It is a measurement marking, not a statement about how any material is used.
How do you convert a volume in millilitres to U-100 graduations?
Because each U-100 graduation is 0.01 mL, a volume in millilitres is converted to graduations by multiplying by 100 — a volume of 0.05 mL reads as 5 graduations on a U-100 barrel. This is a units conversion for reading a measured volume off a graduated scale; it makes no reference to any particular compound.
What is bacteriostatic water, as a reconstitution solvent?
Bacteriostatic water is water containing a small amount of benzyl alcohol, which limits microbial growth in a solution that will be sampled more than once. In a laboratory it is one of the common solvents for returning a lyophilized research compound to solution. Which solvent is appropriate for a given compound is governed by that compound's solubility and the receiving laboratory's validated method, not by this tool.