Molarity (M) is the number of moles of solute dissolved per liter of solution. It is the most common unit of concentration in chemistry, defined as M = n / V where n is moles and V is volume in liters.

How do I calculate molarity from grams?

Divide the mass in grams by the molar mass (g/mol) to get moles, then divide moles by the volume in liters. This calculator handles that conversion automatically when you enter mass and molar mass.

What is the difference between molarity and molality?

Molarity (M) is moles of solute per liter of solution and changes with temperature because liquid volume expands. Molality (m) is moles of solute per kilogram of solvent and is temperature-independent.

Can I enter volume in milliliters?

Yes. Select mL from the unit dropdown next to the volume field and the calculator converts it to liters automatically before computing.

Why does my result show "Infinity"?

This happens if volume is zero. A solution cannot have zero volume. Enter a positive volume to get a valid molarity.

What units does molarity use?

Molarity is expressed in mol/L, also written as M (molar). One molar solution contains one mole of solute per liter of solution.

Molarity Calculator

Name: Molarity Calculator
Availability: InStock
Author: Nham Vu

Enter any two of moles, volume, and molarity to instantly calculate the third.

Solve for

Moles of solute (n)

mol

Volume of solution (V)

Molarity (M)

mol/L

Enter values on the left and click Calculate

Copied!

Summary

Enter any two of moles, volume, and molarity to instantly calculate the third.

How it works

Select which variable you want to calculate: molarity, moles, or volume.
Enter the known values in the input fields that appear.
Optionally enter a molar mass and mass in grams to auto-compute moles.
Click Calculate to see the result with the formula used.
Use the Reset button to clear all fields and start a new calculation.

Use cases

Prepare a solution of known concentration in a chemistry lab.
Convert between grams and moles when molar mass is known.
Determine how much solute is needed for a target concentration.
Find the volume required to dilute a stock solution to a set molarity.
Check stoichiometry calculations in titration experiments.
Verify solution preparation steps in pharmaceutical compounding.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu