ChemBench

Molarity Calculator

Moles of solute per liter of solution.

Mass of solute (g)

Molar mass (g/mol)

Solution volume (L)

Molarity

1.001 mol/L

What you entered

Mass of solute (g): 58.5Molar mass (g/mol): 58.44Solution volume (L): 1

1
Moles = mass ÷ molar mass
58.5 ÷ 58.44= 1.001 mol
2
Molarity = moles ÷ volume
1.001 ÷ 1= 1.001 mol/L

Result

Molarity: 1.001 mol/L

This solution is 1.001 mol/L (M).

Molarity from mass, molar mass, and volume

Molarity is moles of solute per litre of solution. Convert grams to moles first, then divide by the solution volume.

Solute mass	Molar mass	Volume	Moles	Molarity
58.44 g NaCl	58.44 g/mol	1 L	1.0000	1.0000 M
58.44 g NaCl	58.44 g/mol	0.5 L	1.0000	2.0000 M
10 g NaCl	58.44 g/mol	0.25 L	0.1711	0.6845 M
5 g NaCl	58.44 g/mol	0.1 L	0.0856	0.8556 M
180.16 g glucose	180.16 g/mol	2 L	1.0000	0.5000 M
40 g NaOH	40 g/mol	1 L	1.0000	1.0000 M

Molarity uses the volume of the finished solution, not the volume of solvent you started with. Dissolving a solid changes the total volume, which is why you make up to the mark in a volumetric flask.

Mass to moles to concentration

Molarity is found in two steps: divide the solute's mass by its molar mass to get moles, then divide those moles by the total solution volume in liters.

The standard unit for solution chemistry

Molarity (M) is the default concentration unit in labs worldwide because it directly gives the number of reacting particles per liter — essential for titrations, dilutions, and reaction stoichiometry in solution.

Frequently asked questions

I dissolved 11.7 g of NaCl (molar mass 58.44 g/mol) in water to make 500 mL of solution — what is the molarity?

Moles = 11.7/58.44 = 0.200 mol. Volume = 0.500 L. Molarity = 0.200/0.500 = 0.400 M.

How is molarity different from molality?

Molarity (M) is moles per liter of total solution; molality (m) is moles per kilogram of solvent only. Molarity changes with temperature because liquid volume expands, while molality does not. Use the molality calculator when you need a temperature-independent measure.

Can I use molarity for dilution calculations?

Yes — the dilution equation M1V1 = M2V2 relies on molarity. If you need to dilute a stock solution, use the dilution calculator which applies this formula directly.

What is the molarity of pure water?

Pure water has a density of about 1000 g/L and a molar mass of 18.015 g/mol, giving roughly 55.5 M. This value matters in equilibrium expressions involving water as a reactant.