Volume Percent Solution Calculator

Enter the solute and solvent volumes to find the volume percent of your solution.

How it is calculated

The tool treats the two liquid volumes as simply adding up. Total volume: V_total = V_solute + V_solvent. Concentration: v/v % = V_solute / V_total × 100. Here V_solute is the volume of the dissolved liquid (for example ethanol) and V_solvent is the volume of the liquid you add it to (for example water), both in the same unit. Results are shown with two decimals, and the volumes are labelled mL.

The labels say mL, but only the ratio matters, so any unit works as long as both fields use it (the total is then in that unit too). Volumes cannot be negative and they cannot both be zero. Because the tool adds volumes, it gives the percentage you intended by volumes of ingredients; when some liquids are mixed the final volume ends up a little smaller than the sum, and the measured v/v % of the finished liquid can then be slightly higher.

Worked example

You pour 35 mL of ethanol into 215 mL of water. Total volume: 35 + 215 = 250 mL. Volume fraction: 35 / 250 = 0.14. Multiply by 100: 14.00%. The tool also reports the total volume of 250.00 mL and the solute volume of 35.00 mL. If you used 100 mL of solute with no solvent, the result would be 100.00%, and with no solute it would be 0.00%.

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Common mistakes

  • Entering the final total volume as the solvent. The solvent field is the volume of liquid added to the solute; if you already know the 250 mL total, the solvent is 250 − 35 = 215, not 250.
  • Mixing units between the fields, such as the solute in mL and the solvent in litres. Both must use the same unit or the percentage is wrong.
  • Using the tool for a weight-based or powder solute. v/v % compares two liquid volumes; a solid dissolved in a liquid is better described by weight per volume.
  • Expecting the volumes to add exactly for every pair of liquids. The tool assumes they do; for strong mixtures a graduated cylinder reading after mixing may differ slightly.
  • Confusing v/v % with the strength printed on a bottle after dilution. The result is the concentration of the new mixture, not of the original stock liquid.

About this calculator

Volume percent (v/v%) expresses a solution's concentration as the volume of solute divided by the total volume of the solution, times 100 — distinct from weight/volume or mole fraction because both quantities being compared are volumes, which is convenient (and standard) whenever both the solute and the solvent are liquids that mix without a large volume change, such as ethanol in water.

It is the concentration unit printed on rubbing alcohol bottles (e.g., “70% isopropyl alcohol v/v”) and used throughout chemistry labs and cleaning-product formulation. It adds the solute and solvent volumes for the total and reports the v/v%, so you can check a mix you have made or work back from a target percentage to the volumes you need.

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Comments (1)

  • Editorial team

    The tool treats the solute as pure, so a stock that is not 100 percent needs a correction. If you pour 70 mL of 91 percent alcohol into 30 mL of water, the tool reports 70 percent, but the real alcohol volume is 63.7 mL, so the mix is about 63.7 percent. Multiply the solute volume by the stock strength first. Would a stock-strength input help you?

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