🧪 Molarity Calculator
Molarity — moles of solute per liter of solution — is the standard way chemists describe concentration. Enter the moles and the volume in liters and the calculator divides them.
A 2-molar solution, for example, holds 2 moles of solute in every liter: twice the particles, twice the reacting power of a 1-molar one.
How to use this calculator
Enter the moles of solute and the solution volume in liters. The calculator divides them to give molarity in mol/L, plus the millimolar equivalent.
- Type the Moles of solute.
- Type the Volume in liters.
- Read the molarity in mol/L instantly.
- Use the mmol/L line when working with dilute solutions.
Frequently asked questions
What does the Molarity Calculator compute?
It calculates solution concentration as moles of solute divided by liters of solution, reported in mol/L (molar) and in mmol/L.
What is molarity used for?
It is the standard concentration unit in chemistry: reactions, titrations and dilutions are all calculated from it. A 2 M solution contains 2 moles of solute per liter.
Can you give a worked example?
2 moles dissolved in 0.5 liters gives 4.0 mol/L, or 4000 mmol/L.
What if I know grams instead of moles?
Divide the grams by the substance's molar mass in g/mol to get moles first. The Molecular Weight Calculator on this site can give you that molar mass from the chemical formula.