Calculate concentration or compare stock and target solutions. The tool shows the units and formula behind each answer.
Educational calculations only. Not dosing or preparation instructions. Results describe concentration and dilution math. They do not establish safety, solubility, stability, purity or suitability for use.
Understand a solution’s concentration
Enter the solute mass and the final volume of the solution. Add a molar mass if you also want the molar concentration.
Your result
Enter your values, then select Calculate.
How the calculation works
Mass concentration = solute mass ÷ final solution volume. Here, mass is converted to mg and volume to mL. The same numeric value can be expressed in g/L.
Molar concentration = mass concentration in g/L ÷ molar mass in g/mol. The result is mol/L, also written M. A millimolar solution is 0.001 mol/L; a micromolar solution is 0.000001 mol/L.
Compare stock and target concentrations
Use the same solute and the same concentration type for both values. The target must be equal to or lower than the stock concentration.
Your result
Enter your values, then select Calculate.
How the calculation works
C₁ × V₁ = C₂ × V₂. Solving for the stock volume gives V₁ = (C₂ ÷ C₁) × V₂. Concentrations are converted to the same units before the comparison.
This relationship assumes the same solute is conserved, without a reaction, precipitation or other loss. V₂ is the final solution volume. The displayed V₂ − V₁ is an arithmetic difference and does not account for volume contraction or other physical effects.
Calculations run in your browser. This tool does not send or save the values you enter.
Formula references: IUPAC mass concentration, IUPAC amount concentration, NIST SI prefixes, OpenStax dilution.
Choose the calculation you need
Concentration: enter the solute mass and the final solution volume. Supply the molar mass of the exact chemical form if you also want mol/L.
Dilution: enter the stock concentration, target concentration and final solution volume. Both concentrations must describe the same solute and use either mass units or molar units.
Keep the result in context
Use the final solution volume, which is not necessarily the amount of liquid added. Calculations cannot confirm identity, purity, sterility, stability, solubility or experimental suitability. This tool does not recommend doses, routes, schedules or preparation procedures.