Calculate or reverse-solve percentage strength for w/v, w/w, and v/v solutions. Convert units and see ratio strength, solvent amount, and concentration.

Choose a solve target, then complete the visible required fields marked with *.

Related Calculators

Percentage Strength Formula

The following formulas are used to calculate percent concentration. Choose the one that matches the convention you are using (% w/v, % w/w, or % v/v).

% (w / v) & = (mₛₒₗᵤₜₑ) / (Vₛₒₗᵤₜᵢₒₙ) × 100 \ % (w / w) & = (mₛₒₗᵤₜₑ) / (mₛₒₗᵤₜᵢₒₙ) × 100 \ % (v / v) & = (Vₛₒₗᵤₜₑ) / (Vₛₒₗᵤₜᵢₒₙ) × 100

Variables:

  • Mass of Solute – The mass of the solute that is dissolved in the solution (commonly expressed in grams for % w/v or % w/w).
  • Volume of Solute – The volume of the solute (commonly expressed in milliliters for % v/v).
  • Volume of Solution – The total volume of the solution (solute + solvent), commonly expressed in milliliters for % w/v and % v/v.
  • Mass of Solution – The total mass of the solution (solute + solvent), commonly expressed in grams for % w/w.

For % w/v, the result represents grams of solute per 100 mL of solution; for % w/w, grams of solute per 100 g of solution; and for % v/v, milliliters of solute per 100 mL of solution.

What is Percentage Strength?

Percentage strength is a way to express solution concentration as a percent using a specified convention. The most common conventions are % w/v (weight per volume), % w/w (weight per weight), and % v/v (volume per volume). For example, 5% w/v means 5 g of solute per 100 mL of solution, while 5% w/w means 5 g of solute per 100 g of solution.

How to Calculate Percentage Strength?

The following steps outline how to calculate the percentage strength of a solution.

  1. Choose the percent convention you need: % w/v, % w/w, or % v/v.
  2. Measure the corresponding solute amount (mass for % w/v or % w/w; volume for % v/v).
  3. Measure the corresponding solution amount (solution volume for % w/v or % v/v; solution mass for % w/w).
  4. Use the matching formula and multiply by 100 to express the ratio as a percent.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge (example shown for % w/v).

Mass of Solute (grams) = 5 grams

Volume of Solution (milliliters) = 250 milliliters, so Percentage Strength (% w/v) = (5 ÷ 250) × 100 = 2% w/v.