Calculator
Percent solution (%w/v · %v/v)
Calculate percent concentrations for laboratory solutions. Pick %w/v for solid solutes, %v/v for liquid solutes.
Percent (w/v)
10.000 %
What % w/v, % v/v and % w/w mean
% w/v is grams of solute per 100 mL of solution, % v/v is millilitres of solute per 100 mL of solution, and % w/w is grams per 100 g. They are not interchangeable: a 70% v/v ethanol solution is not 70% w/w, because ethanol is less dense than water.
Worked example
For 250 mL of 5% w/v NaCl: 5 × 250 ÷ 100 = 12.5 g. Dissolve 12.5 g in less than 250 mL of water, then make up to 250 mL.
Common mistakes
- Adding the solute to the full volume of solvent instead of making the solution up to volume.
- Treating % w/v as % w/w for dense solutions.
- Forgetting the water of hydration when the solute is a hydrate.
Learn the concept
FAQ
What is %w/v?
%w/v (weight per volume) is grams of solute per 100 mL of solution. A 10 %w/v solution contains 10 g of solute per 100 mL.
What is %v/v?
%v/v (volume per volume) is mL of solute per 100 mL of solution. Use it when the solute is a liquid (e.g. 70 %v/v ethanol).
When should I use w/v vs v/v?
Use w/v for solid solutes (salts, buffers, sugars). Use v/v for liquid solutes (alcohols, acids, organic solvents).