Dilution Calculator

What Is Dilution?

Dilution is the process of reducing the concentration of a solution by adding more solvent (usually water). This calculator uses the standard dilution equation: C1 × V1 = C2 × V2, where C1 is the initial concentration, V1 is the initial volume, C2 is the desired final concentration, and V2 is the desired final volume. Enter any three values to find the fourth. The formula works for any concentration unit (molarity, percentage, mg/mL) as long as both concentrations use the same unit.

Common Dilution Scenarios

Laboratory work frequently requires preparing specific concentrations from stock solutions. If you have a 10 M stock solution and need 500 mL of a 1 M working solution, the formula gives: V1 = (1 × 500) / 10 = 50 mL. So you take 50 mL of stock and add 450 mL of solvent to reach 500 mL total. In cleaning, disinfecting, and industrial applications, the same formula applies to diluting concentrated products to their recommended working strength.

Serial Dilutions

Serial dilutions involve repeating the dilution process multiple times to achieve very low concentrations. A 1:10 serial dilution performed three times produces a final dilution of 1:1000. Each step takes a portion of the previous solution and dilutes it by the same factor. Serial dilutions are standard practice in microbiology (bacterial counts), immunology (antibody titers), and pharmacology (dose-response curves). Accuracy at each step is critical because errors compound through subsequent dilutions.

Practical Tips

Always add the concentrated solution to the solvent, not the reverse – this is especially important for acids, where adding water to concentrated acid can cause violent reactions. Use volumetric flasks for precise work. When accuracy matters less (cleaning, general lab prep), graduated cylinders or measuring cups are sufficient. Label every diluted solution with the concentration, date, and preparer to avoid confusion and ensure traceability.

Frequently asked questions