Molarity Dilution Calculator

About this calculator

The dilution equation C₁V₁ = C₂V₂ holds because the total moles of solute stay constant when a solution is diluted with solvent — only the volume changes, so concentration falls in exact proportion to how much the volume grows. Solving for the stock volume needed, V₁ = C₂V₂/C₁, tells you exactly how much of a concentrated stock solution to measure out before topping it up to the target volume with solvent.

This is one of the first calculations taught in general chemistry lab courses, and it's used constantly in real lab work: preparing buffers and reagents at a working concentration from a concentrated stock, pharmacists and pharmacologists diluting drug stocks to a dosing concentration, and molecular biologists diluting DNA, enzyme, or antibody stocks for PCR, assays, and cell culture. Getting it right matters because both under- and over-diluting a reagent can invalidate an experiment or a compounded preparation.