What Is Volume Percent (%v/v)?
Volume percent, written as %v/v or % (v/v), expresses the concentration of a liquid solute within a solution as a percentage of the total volume. It is one of the most common ways to describe the strength of liquid-in-liquid mixtures such as alcoholic beverages, cleaning solutions, and laboratory reagents. For example, a wine labeled "12% v/v" contains 12 mL of pure ethanol in every 100 mL of wine.
How to Use This Calculator
Enter two values: the volume of solute (the substance being dissolved) and the volume of solution (the total final volume). The calculator divides the solute volume by the solution volume and multiplies by 100 to return the volume percent. Make sure both volumes use the same unit — milliliters, liters, or gallons — since the result is a ratio and the units cancel out.
The Formula Explained
The equation is:
$$\%\,v/v = \frac{\text{Volume of solute (mL)}}{\text{Volume of solution (mL)}} \times 100$$
Note that the solution volume is the total volume of the finished mixture, not just the volume of the solvent you started with. Because mixing liquids can cause slight volume contraction or expansion, the true solution volume should be measured after mixing for best accuracy.
Worked Example
Suppose you dissolve 25 mL of acetic acid in enough water to make 200 mL of solution. The volume percent is $$(25 \div 200) \times 100 = 12.5\% \ v/v.$$ So the solution is 12.5% acetic acid by volume.
FAQ
Is %v/v the same as %w/v? No. %v/v compares volume to volume, while %w/v (weight/volume) compares the mass of solute in grams to the volume of solution in milliliters.
What units should I use? Any volume unit works as long as both inputs use the same one, because the ratio is dimensionless.
Can %v/v exceed 100%? Not for a real solution — the solute volume cannot exceed the total solution volume. A result above 100% means your inputs were swapped or measured incorrectly.
