Calculate percent solution concentration (w/v, w/w or v/v) from solute and final solution amounts, or find how much solute you need to make a solution.

w/v means grams per 100 mL of final solution. Use final solution amounts, not solvent amounts.

Optional settings

Percent Solution Formula

State the concentration basis before using a percent solution. The formulas below use total solution mass for w/w, final solution volume for w/v, and pure-component volume divided by final solution volume for the v/v convention used here.

w / w (%) = solute mass / final solution mass × 100 w / v (%) = solute mass (g) / final solution volume (mL) × 100 v / v (%) = component volume / final solution volume × 100
  • P is the numerical concentration value on the stated w/w, w/v or v/v basis.
  • For w/w, use solute mass and total solution mass in compatible mass units. For w/v, normalize solute mass to grams and final solution volume to millilitres.
  • For v/v here, use pure-component volume and measured final solution volume in compatible volume units.

Mass and volume are different quantities. Matching mass units are needed for w/w and matching volume units for v/v; w/v deliberately uses grams of solute per 100 mL of final solution. Final solution volume includes the whole mixture and is not the volume of solvent. Do not assume that component volumes add.

Always report the basis with the answer. For example, 100% w/v means 100 g per 100 mL, not pure solute. A calculated ratio does not establish solubility or that a mixture can be prepared. Converting between mass and volume requires the applicable density at the stated composition and temperature.

Percent Solution Definition

Percent solution is a concentration description that needs a stated basis. Mass percent (w/w) expresses solute mass per 100 mass units of total solution. The w/v convention expresses grams of solute per 100 mL of final solution. The v/v convention used here expresses pure-component volume per 100 volume units of final solution. These numerical values are not interchangeable.

How to calculate a percent solution?

  1. First, determine the units you wish to use. For this example, we will look at the percent by mass.
  2. Next, determine the mass of the solute. For this example, the mass of the solute is 10 g.
  3. Next, determine the mass of the solution. For this example, the mass of the solution is 100 g.
  4. Finally, calculate the percent solution using the formula: 10 g/100 g * 100 = 10% of the solution by mass.

FAQ

What is a percent solution?

A percent solution describes concentration on a stated basis. w/w compares solute mass with total solution mass; w/v states grams of solute per 100 mL of final solution; v/v here compares pure-component volume with final solution volume. The basis must accompany the number.

What does a 5 percent solution mean?

5% w/w means 5 g of solute per 100 g of total solution. 5% w/v means 5 g per 100 mL of final solution. 5% v/v here means 5 mL of pure component per 100 mL of final solution. Final solution volume is not solvent volume, so the basis cannot be omitted.

What is the difference between a volume percent and mass percent?

Mass percent compares masses. The v/v convention used here compares pure-component volume with final solution volume. The values need not be similar: densities depend on substance, composition and temperature, and volumes can change on mixing. Converting between mass and volume requires the relevant density; do not assume that solvent and component volumes add.