Density to Molarity Converter

Summary

Enter solution density, mass fraction (weight percent), and solute molar mass to instantly calculate molarity in mol/L.

How it works

1. Enter the solution density in grams per milliliter (g/mL) from the reagent label.
2. Enter the mass fraction (weight percent) of the solute in the solution.
3. Enter the molar mass of the pure solute in grams per mole (g/mol).
4. Click Calculate — the tool applies M = (ρ × w% × 10) ÷ M_r.
5. Review the step-by-step derivation showing each unit conversion.
6. Use the preset buttons for common reagents to auto-fill known values instantly.

Use cases

• Preparing standard solutions from concentrated stock reagents in the lab.
• Verifying molar concentration of commercially supplied chemicals.
• Calculating volumes needed for dilution using the C1V1 = C2V2 relation.
• Stoichiometric calculations for titrations and reactions.
• Teaching unit conversion between density, weight percent, and molarity.
• Cross-checking reagent quality certificates against expected molarity.
• Formulating buffer solutions at precise molar concentrations.
• Converting any solute/solvent combination — not limited to acids.

Frequently Asked Questions