Molarity Calculator

Use this molarity calculator to find molar concentration from moles of solute and liters of solution. It is useful for chemistry classes, lab preparation checks, dilution planning, and solution documentation.

How to use this calculator

Enter Moles of solute in mol and Volume in liters. The calculator returns Molarity in M (mol/L) and repeats the entered moles and volume so you can check the setup. Volume must be positive, while moles may be zero.

Formula

Molarity, written as M, is moles of solute per liter of solution.

M = moles ÷ liters

The same relationship in the form is:

$M = moles\ of\ solute \div volume\ in\ liters$

For example, 0.5 mol of solute in 2 L of solution gives 0.5 ÷ 2 = 0.25 M. A 1.0 M solution contains 1 mole of solute in each liter of final solution.

Lab notes

Use final solution volume, not just solvent volume. If your amount is in grams, convert grams to moles using molar mass before using this form. Related tools include the volume converter, density converter calculator, and scientific notation calculator.

Common mistakes

• Entering milliliters as liters.
• Confusing grams with moles.
• Rounding before reporting significant figures.