Molarity & Dilution Calculator
Concentration, mass needed, and the dilution equation.
How it works
Molarity is moles of solute per litre of solution: M = n / V, and moles are mass divided by molar mass.
Dilution uses C₁V₁ = C₂V₂ — the amount of solute does not change, only the volume it is spread through. Rearranged, the stock volume you need is C₂V₂ / C₁.
One practical detail the equation hides: molarity is per litre of *solution*, not per litre of solvent. Dissolve the solid in part of the volume, then make up to the mark. Adding solid to a full litre gives more than a litre and a concentration that is quietly wrong.