Percentage Concentration to Molarity Calculator

Converting a percentage concentration to molarity is a common step in lab prep — this calculator does it for all three percent types: % w/v, % w/w, and % v/v. Select your Percent Type, then enter the Percentage, Molar Mass of your solute, and Density (required for % w/w and % v/v) to get the Molarity in mol/L. Secondary outputs show the detected concentration type and the exact formula applied. Also try the Mass Percent Calculator.

%
g/mol

Molecular weight of the solute

g/mL

Solution density (w/w) or solute density (v/v). Not needed for w/v.

Results

Molarity

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Concentration Type

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Formula Used

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Frequently Asked Questions

What is the difference between w/w, w/v, and v/v percentage?

w/w % is grams of solute per 100 grams of solution, w/v % is grams of solute per 100 mL of solution, and v/v % is milliliters of solute per 100 mL of solution. Each requires different formulas for molarity conversion. See also our Alligation Calculator.

When do I need to enter density for the calculation?

For w/v percentages, density is not needed. For w/w percentages, you need the solution density. For v/v percentages, you need the solute density to convert volume to mass.

How is molarity calculated from percentage concentration?

The formula depends on the percentage type: w/v uses M = (% × 10) / Molar Mass, w/w uses M = (% × density × 10) / Molar Mass, and v/v uses M = (% × solute density × 10) / Molar Mass. The factor 10 converts per 100 mL to per liter.

What units should I use for molar mass and density?

Enter molar mass in g/mol and density in g/mL. The calculator will automatically handle the unit conversions to give molarity in mol/L (M). You might also find our Mixing Ratio Calculator useful.

Why is the factor 10 used in the calculation?

The factor 10 converts the concentration from 'per 100 mL' (percentage basis) to 'per liter' (molarity basis), since 1 liter = 1000 mL and 1000/100 = 10.

Can I calculate molarity for very dilute or concentrated solutions?

Yes, the calculator works for any concentration from 0.001% to 100%. However, very high concentrations may require accurate density values for precise results.

What does the significant figures option do?

When enabled, the result is rounded to a sensible number of significant figures based on the precision of your input values, following standard scientific notation practices.