How do I find the molar mass to enter?

Molar mass is the sum of atomic weights of every atom in the compound's formula, in g/mol (e.g. NaCl = 22.99 + 35.45 = 58.44 g/mol). You can use this calculator's companion Molecular Weight Calculator to compute it from a chemical formula.

What's the difference between molarity and molality?

Molarity (mol/L) is moles of solute per litre of total solution, which this calculator computes. Molality (mol/kg) is moles of solute per kilogram of solvent only, and is temperature-independent since it doesn't rely on volume, which can expand or contract with temperature.

Molarity Calculator

Solve for molarity, mass or volume of a solution.

How this is calculated

Molarity = (Mass ÷ Molar mass) ÷ Volume

Assumptions used in this calculation

Volume is total solution, not solvent: Volume refers to the final total solution volume after the solute is dissolved and topped up, not the volume of solvent added before mixing, consistent with the standard molarity definition (mol/L of solution).
Complete dissolution at room temperature: Assumes the solute fully dissolves and the solution is measured near 25°C; molarity of a fixed mass will change with temperature because liquid volume expands or contracts.

About this calculator

The molarity calculator solves for molarity, solute mass or solution volume given the molar mass of the solute and the other two values.

Worked example

58.44g NaCl in 1L

Result: 1 mol/L

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Frequently asked questions

Molecular Weight Calculator

Calculate the molecular weight of a chemical compound from its formula.

Density Calculator

Solve for density, mass or volume when you know the other two.

Molarity Calculator

About this calculator

Frequently asked questions

How do I find the molar mass to enter?

What's the difference between molarity and molality?

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