Dilution Calculator (C1V1 = C2V2)

This dilution calculator uses the relationship C1V1 = C2V2 and solves for whichever of the four variables you do not know: the stock concentration (C1), the volume of stock to use (V1), the desired final concentration (C2), or the total final volume (V2). Diluting a concentrated stock solution is one of the most common tasks in chemistry, biology, microbiology, and everyday settings such as brewing, pool maintenance, cleaning products, and hydroponics. The principle is straightforward: when you dilute a solution by adding solvent (usually water), the amount of solute does not change, so the product of concentration and volume stays constant before and after. You choose which variable to solve for, enter the three known values, and the calculator returns the answer along with the volume of diluent to add and the dilution factor. The only rule is that units must be consistent: use the same concentration unit (mol/L, percent, g/L) for both concentrations, and the same volume unit (mL or L) throughout. The calculated diluent volume is the final volume minus the stock volume, and the dilution factor is how many times more dilute the final solution is compared to the stock. Note that you cannot dilute to a concentration higher than the stock, so C2 must always be less than C1. The default example dilutes a 10 mol/L stock to 2 mol/L by taking 25 mL of stock and making it up to a final volume of 125 mL with diluent. Results are theoretical and assume ideal mixing with no volume change on mixing.

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Use the same concentration unit for C1 and C2 (mol/L, %, g/L) and the same volume unit for V1 and V2 (mL or L). The final concentration must be lower than the stock concentration.