What Is a Molarity Calculator?
Molarity (M) measures the concentration of a solution — moles of solute per liter of solution. This calculator finds molarity from mass, molar mass, and volume, or works in reverse to find how much mass you need for a target molarity.
How to Use the Molarity Calculator
- Choose whether to find molarity or find the mass needed.
- Enter the molar mass of your solute and the solution volume.
- Enter mass (or target molarity, depending on mode).
Molarity Formula
Worked Example
Moles: 10 ÷ 58.44 ≈ 0.1711 mol
Molarity: 0.1711 mol ÷ 1 L ≈ 0.171 M
Understanding Your Results
Molarity tells you how concentrated a solution is in moles per liter — essential for chemistry lab work, dilutions, and stoichiometry calculations. To prepare a solution of a specific molarity, use "Find Mass Needed" mode to determine exactly how much solute to weigh out.
Common Mistakes to Avoid
- Confusing molarity (moles/liter) with molality (moles/kilogram of solvent) — they're different concentration measures.
- Using the wrong molar mass for your specific solute — always verify from a reliable chemistry reference.
Frequently Asked Questions
Molarity (M) is a measure of solution concentration, expressed as moles of solute per liter of solution.
Divide the moles of solute (mass divided by molar mass) by the volume of solution in liters.
Molarity measures moles of solute per liter of solution (volume-based), while molality measures moles of solute per kilogram of solvent (mass-based) — they're related but not interchangeable.
Multiply the target molarity by the volume (in liters) to get moles needed, then multiply by the molar mass to get the mass to weigh out.
Sum the atomic masses of all atoms in the molecular formula using a periodic table, or check a reliable chemistry reference for the compound's molar mass.