ppm to Molarity Calculator

About this calculator

This calculator converts a dilute concentration expressed in ppm (parts per million, treated as mg per litre for water-based solutions) into molarity (mol/L) using the solute's molar mass: molarity = ppm ÷ (1000 × molar mass). It works because 1 ppm in an aqueous solution is essentially 1 mg of solute per litre of solution, so dividing by the molar mass converts mass to moles.

Analytical chemists, environmental scientists, and lab technicians use this conversion constantly — water-quality standards (like EPA or WHO drinking-water limits for lead, nitrate, or chlorine) are published in ppm or mg/L, but equilibrium and titration calculations need molarity. Enter the ppm value and the molar mass of the compound to get mol/L.