How the molarity calculator works
Molarity is the concentration of a solution in moles of solute per liter of solution. Choose whether to find molarity, moles, or volume, enter the other two, and the tool solves the relationship. It also shows millimoles and the volume in milliliters for convenience in the lab.
The molarity formula
Molarity equals moles divided by volume in liters. Rearranged, moles equal molarity times volume, and volume equals moles divided by molarity. A one molar solution contains one mole of solute per liter. Keeping volume in liters is the most common source of error, so convert milliliters first.
Getting moles from mass
If you start from a mass rather than moles, first divide the mass in grams by the substance molar mass in grams per mole to get moles, then use this tool. For example, 58.5 grams of table salt is about one mole, since its molar mass is roughly 58.5 grams per mole.
Preparing solutions
To make a solution of a target molarity, multiply the molarity by the volume to find the moles needed, convert to grams using the molar mass, dissolve, and dilute to the final volume. The tool helps with the moles and volume side; always add solute to solvent carefully and follow lab safety practices.
Frequently asked questions
How do I calculate molarity? Divide the moles of solute by the volume of solution in liters.
What is a 1 molar solution? One that contains one mole of solute per liter of solution.
How do I get moles from grams? Divide the mass in grams by the molar mass in grams per mole.