Chemistry

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Percentage Concentration to Molarity Calculator.

Convert an explicitly selected percentage basis to molarity using molar mass and required density.

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Molarity: 0.898357 mol/L

Molarity

0.898357mol/L
Mass concentration: 52.5 g/L

Mass concentration

52.500000g/L

How to Use

Every model convention and source-dependent parameter is visible. Results update automatically after each edit.

Use Cases

Preparing solutions in a lab

Convert a stock solution's percentage concentration to molarity to accurately dilute it to a desired molar concentration for experiments.

Example: Convert 37% w/w HCl (molar mass 36.46 g/mol, density 1.19 g/mL) to molarity.

Checking reagent labels

Verify the molarity of a commercial reagent labeled as a percentage to ensure it meets the required concentration for a protocol.

Example: Check the molarity of a 10% w/v NaOH solution (molar mass 40 g/mol, density 1.11 g/mL).

Frequently Asked Questions

How do I use the Percentage Concentration to Molarity Calculator?
Enter the percentage concentration (e.g., 37% w/w), the molar mass of the solute, and the density of the solution. Select the percentage basis (w/w, w/v, v/v) and the calculator will compute the molarity in mol/L.
What percentage bases are supported?
The calculator supports weight/weight (w/w), weight/volume (w/v), and volume/volume (v/v) percentage concentrations. Choose the correct basis for your solution to get an accurate molarity.
Why is density required for the calculation?
Density is needed to convert between mass and volume of the solution. Molarity is moles per liter of solution, so you must know the solution's density to relate the percentage concentration to volume.

Tips & Common Mistakes

Tips

  • Always select the correct percentage basis (w/w, w/v, v/v) to match how the concentration is expressed.
  • Use the most accurate molar mass from the periodic table or a reliable source for your solute.
  • Ensure density is in g/mL (or convert to g/L) to get molarity in mol/L correctly.
  • Double-check your inputs for unit consistency; the calculator assumes standard units.

Common Mistakes to Avoid

  • Forgetting to convert density from g/mL to g/L when using the formula, leading to a factor of 1000 error.
  • Using w/w percentage but entering density of the solvent instead of the solution.
  • Mixing up percentage bases, e.g., using w/v when the label says w/w, which changes the calculation.

Last updated: August 13, 2026