Molarity & Dilution Calculator (C1V1=C2V2)

Use the dilution formula C1V1 = C2V2 to calculate any one of the four values (concentration or volume, before and after dilution) from the other three.

Tips

  • Selecting the variable you want in "Value to solve for" reveals the remaining three input fields. Enter the three values already fixed by your experiment.
  • Volume is standardized in mL and concentration in mol/L. If your numbers use different units (such as L), convert them before entering.
  • When mixing solutions, it's safest to follow the "add acid to water" principle: add the concentrated stock solution gradually into a small amount of solvent, then top it up with more solvent.
  • For accurate dilution, we recommend using precision glassware such as a volumetric pipette or a volumetric flask with fine graduations.

Frequently Asked Questions

C1V1=C2V2 is used to calculate "dilution" — making a lower-concentration solution from a higher-concentration one. It's based on the principle that the amount of solute (in moles) doesn't change before and after dilution.

Diluting a solution keeps the amount of solute the same while the volume increases, so the molarity (mol/L) decreases in proportion to the volume increase. For example, doubling the volume halves the concentration.

No, they're different. Molarity (mol/L) expresses the amount of solute (in moles) dissolved per liter of solution, while mass percent expresses the mass of solute as a proportion of the solution's total mass. Converting between them requires knowing the solution's density.

Yes. Molarity (mol/L) is calculated as "moles of solute ÷ volume of solution (L)". If you only know the mass, you'll need to convert it to moles using the molar mass first.
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Side Note — Where the Unit "Molarity" Comes From

Molarity (mol/L, also written with the symbol M) only became possible as a concept thanks to the "Avogadro constant" (about 6.022×10²³) proposed by the Italian physicist Amedeo Avogadro in the late 19th century — a constant that bridges the gap between the amount of a substance and the number of particles it contains. Before that, solution concentration could only be expressed as a mass ratio, which made handling the quantitative relationships of chemical reactions (stoichiometry) extremely cumbersome.

The advent of molarity let chemists describe reactions using a unified scale of "how many moles of substance are dissolved" rather than "how many grams." Combined with the fact that the coefficients in a chemical equation directly represent molar ratios, this became the foundation of quantitative analytical chemistry — including titration — that is still widely used today.

The "volumetric flask" used for dilution in the laboratory is glassware designed to measure a specific volume accurately at a specific temperature (usually 20°C). Because both glass and liquids change volume slightly with temperature, controlling room temperature is also considered a factor affecting dilution accuracy in precise analytical chemistry work.

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