Molarity Calculator
Calculate the molarity of a solution from solute mass, molar mass and volume.
Molarity = moles ÷ volume. 58.44 g/mol is NaCl (common example).
What is Molarity Calculator?
Molarity is the concentration of a solution expressed as the number of moles of solute dissolved in one liter of solution. It is the most commonly used concentration unit in chemistry because it directly relates volumes and quantities for reactions.
To find molarity you need the mass of solute, its molar mass, and the final solution volume. This calculator performs all three steps at once.
How does the Molarity Calculator work?
Moles are obtained by dividing the solute's mass in grams by its molar mass in grams per mole.
Molarity then divides the moles by the solution volume in liters, giving concentration in mol/L, the standard SI unit.
How to use the Molarity Calculator?
- Enter the mass of the solute in grams.
- Enter the molar mass of the solute in g/mol, or use 58.44 for NaCl.
- Enter the final solution volume in liters.
- Read the number of moles and the resulting molarity.
Example
Try the calculator with your own numbers
- Enter your values in the input fields above.
- Adjust the values to match your situation.
- The result updates instantly as you change the inputs.
Benefits of using the Molarity Calculator
- Prepare solutions to an exact concentration with confidence.
- Know exactly how much solute to weigh for a target molarity.
- Avoid arithmetic errors when converting between mass, moles and volume.
Who should use the Molarity Calculator?
- Students practising problems and verifying homework answers.
- Teachers preparing examples and checking student work.
- Engineers and analysts who need quick, reliable calculations.
- Anyone who wants to double-check manual arithmetic.
Tips for getting the most out of the Molarity Calculator
- Check your inputs for typos — a single wrong digit changes the result completely.
- Use the result to verify your manual working, not to replace understanding.
- Try a simple case first (like 0 or 1) to make sure the output makes sense.
Frequently Asked Questions
What is a mole?
A mole is a standard amount of substance equal to roughly 6.022 × 10^23 particles. One mole of a compound has a mass equal to its molar mass in grams, so 1 mole of NaCl weighs 58.44 g.
Is molarity the same as molality?
No. Molarity is moles of solute per liter of solution, while molality is moles of solute per kilogram of solvent. Molarity depends on temperature because volume changes with it, whereas molality does not.
Why is 58.44 g/mol used as the default molar mass?
58.44 g/mol is the molar mass of sodium chloride (NaCl), combining 22.99 g/mol for sodium and 35.45 g/mol for chlorine. It is a common default because NaCl solutions are widely prepared in labs.
This calculator turns a tedious calculation into an instant answer, so you can focus on understanding the concept instead of the arithmetic.
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