Molarity Calculator

Find the molar concentration (mol/L) of a solution from the mass of solute, its molar mass and the solution volume.

g/mol
Sum of atomic masses in the formula. Acetic acid (CH₃COOH) = 60.052 g/mol; NaCl = 58.44 g/mol.
The final volume of the whole solution, not the volume of solvent added.
Molarity
0.839273 mol/L (M)
Amount of solute
0.419636 mol
Millimolar
839.27 mmol/L (mM)
Mass concentration
50.4 g/L

Estimate generated with SortedSums: https://sortedsums.com/molarity-calculator/. For informational purposes only; verify before relying on it.

How it’s calculated

Molarity is moles of solute per liter of solution. Convert the mass of solute to moles with its molar mass, then divide by the solution volume in liters.

n (mol) = mass (g) ÷ molar mass (g/mol) M (mol/L) = n ÷ V (L)

Example (OpenStax Chemistry 2e): 25.2 g of acetic acid (60.052 g/mol) in 0.500 L of vinegar is 25.2 ÷ 60.052 = 0.4196 mol, and 0.4196 ÷ 0.500 = 0.839 M.

Frequently asked questions

What is the difference between molarity and molality?

Molarity is moles per liter of solution; molality is moles per kilogram of solvent. Molality does not change with temperature.

How do I find molar mass?

Add the atomic masses of every atom in the formula from the periodic table. For NaCl: 22.99 + 35.45 = 58.44 g/mol.

How do I make a solution of a given molarity?

Weigh out molarity × volume (L) × molar mass grams of solute, dissolve it in less solvent, then top up to the final volume in a volumetric flask.

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Sources

Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.

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