Percentage Concentration to Molarity Calculator
Convert a percentage concentration (w/w or w/v) to molarity in mol/L. Enter the mass percent of the solute, its molar mass (from the periodic table or data sheet), and for w/w solutions the solution density — the calculator gives you molarity instantly.
Concentration type
%
g/mol
g/mL
Moles of solute per litre of solution
- 1
Concentration (g/L)
37 × 1.18 × 10 = 436.6% w/w × density × 10 converts mass fraction to g per litre. - 2
Molarity
436.6 ÷ 36.46 = 11.9748
How does this calculator work?
Molarity = (% × 10) ÷ Molar Mass for w/v solutions; Molarity = (% × Density × 10) ÷ Molar Mass for w/w solutions. Enter the percentage, molar mass from the periodic table, and (for w/w) the solution density from a reference table to get the concentration in mol/L.
Formula
How this is calculated
Two types of percentage concentration are common in chemistry: w/v (weight-to-volume, grams of solute per 100 mL of solution) and w/w (weight-to-weight, grams of solute per 100 g of solution). Molarity, by contrast, measures moles of solute per litre of solution.
For a w/v solution, converting is straightforward: % w/v × 10 gives the concentration in g/L, and dividing by the molar mass converts to mol/L (molarity). For w/w, you first need the solution density in g/mL to convert grams of solution to millilitres: concentration (g/L) = % × density × 10, then divide by molar mass.
Density values depend on both the solute and the concentration — use a published density table for your specific compound (standard references are available in handbooks such as the CRC). Molar mass is the sum of atomic masses of all atoms in one formula unit, found on the periodic table.
Frequently asked questions
% w/v (weight-per-volume) is grams of solute per 100 mL of solution — common for aqueous lab reagents. % w/w (weight-per-weight) is grams of solute per 100 g of solution — common on commercial bottles of concentrated acids and bases.
Molarity is defined per litre of solution (a volume). % w/v already refers to volume, so no density is needed. % w/w refers to mass of solution, so you need the density to convert mass to volume before calculating molarity.
Bottle labels for concentrated reagents (e.g. HCl, H₂SO₄) usually state the density. Alternatively, look up density tables in the CRC Handbook of Chemistry and Physics or NIST WebBook for your solute and concentration range.
Also known as
TG we-Calculate Editorial Team. (2026). Percentage Concentration to Molarity Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/percentage-concentration-to-molarity-calculator
TG we-Calculate Editorial Team. "Percentage Concentration to Molarity Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/percentage-concentration-to-molarity-calculator.
TG we-Calculate Editorial Team, "Percentage Concentration to Molarity Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/percentage-concentration-to-molarity-calculator
@misc{wecalculate_percentage_concentration_to_molarity_calculator, title = {Percentage Concentration to Molarity Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/percentage-concentration-to-molarity-calculator}}, year = {2026}, note = {TG we-Calculate} }
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