Dilution Calculator

Use C1V1 = C2V2 to dilute any stock solution to a target concentration

Dilution Calculator


Diluting a stock solution to a lower concentration is one of the most common tasks in chemistry, biology, and laboratory work. Whether you are preparing a working solution, adjusting reagent strength, or reducing concentration for an experiment, the standard dilution equation — C1V1 = C2V2 — gives you the exact volume needed. This dilution calculator instantly computes the final volume and the amount of diluent required.

What is the starting concentration, starting volume, and target concentration?

Starting concentration (C1, %): Starting volume (V1, mL): Target concentration (C2, %):    


How dilution calculations work


Dilutions follow the equation:

C1 × V1 = C2 × V2

Here:

  • C1 = starting concentration
  • V1 = starting volume
  • C2 = target concentration
  • V2 = final total volume after dilution

Rearranging the equation gives:

V2 = (C1 × V1) / C2

Example: Diluting 50 mL of a 10% stock solution down to 2% V2 = (10 × 50) / 2 = 250 mL total Diluent to add = 250 − 50 = 200 mL

This method works for percent solutions, molarity, mass/volume concentrations, and any dilution where concentration scales linearly.



Examples of common lab dilutions


Example 1: Diluting a disinfectant
C1 = 8%, V1 = 100 mL, C2 = 2% V2 = (8 × 100) / 2 = 400 mL Add 300 mL of water.

Example 2: Preparing a working reagent
C1 = 5%, V1 = 20 mL, C2 = 1% V2 = (5 × 20) / 1 = 100 mL Add 80 mL of diluent.

Example 3: Reducing concentration for a titration
C1 = 12%, V1 = 10 mL, C2 = 3% V2 = (12 × 10) / 3 = 40 mL Add 30 mL of diluent.

Example 4: Making a calibration standard
C1 = 4%, V1 = 25 mL, C2 = 1% V2 = (4 × 25) / 1 = 100 mL Add 75 mL of diluent.

These examples show how dilution calculations apply to chemistry labs, biology experiments, cleaning solutions, and industrial formulations.



Why the C1V1 = C2V2 equation works


The dilution equation is based on the idea that the amount of solute stays constant — only the volume changes. When you add diluent (usually water), the concentration decreases because the solute is spread out over a larger total volume.

This makes the equation ideal for preparing:

  • working solutions
  • buffer dilutions
  • chemical standards
  • cleaning agents
  • biological reagents


For more percentage tools — including everyday, math, and scientific calculators — visit our percentage calculator homepage.



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