Percentage Concentration to Molarity Calculator

Percentage concentration and molarity describe solution composition on different bases. Molarity is moles of solute per liter of final solution, while a percentage can compare mass with volume, mass with mass, or volume with volume. A correct conversion therefore begins by identifying whether the stated percentage is weight/volume, weight/weight, or volume/volume. The same numerical percentage can correspond to different molarities under these conventions. For weight/volume concentration, the percentage states grams of solute per 100 milliliters of solution. Multiplying by 10 converts that amount to grams per liter, and dividing by the solute molar mass gives moles per liter. Thus a 5 percent w/v sodium chloride solution contains 50 grams per liter. With a molar mass of 58.44 grams per mole, its molarity is approximately 0.8556 mol/L. Density is not needed because the percentage already relates mass to final volume. Weight/weight concentration states grams of solute per 100 grams of solution. Solution density converts one liter of solution into mass: one liter has a mass of density multiplied by 1,000 grams. Applying the mass fraction and dividing the resulting solute grams by molar mass gives molarity. Density must correspond to the complete solution at the relevant temperature and concentration, not merely the pure solvent. Volume/volume concentration states milliliters of liquid solute per 100 milliliters of solution. To convert solute volume to mass, this calculator uses the entered density as the solute density. Multiplying the volume fraction by one liter and by solute density gives grams per liter, which are then divided by molar mass. This has the same numerical equation as the weight/weight case, but the physical meaning of density differs. For mixtures with volume contraction or nonideal behavior, use experimentally appropriate data. Molarity is temperature dependent because solution volume changes with temperature, while mass fractions are generally not. Density should therefore be measured or sourced at a temperature consistent with the intended use. Also distinguish molarity from molality, which is moles per kilogram of solvent. This calculator assumes pure-solute molar mass and consistent units. Hydrates, mixtures, assay corrections, and commercial concentration specifications may require additional composition information. For analytical or regulated work, retain enough significant figures during conversion and round only the final result.