Molar Concentration Calculator
A free molar concentration calculator that finds the concentration of a solution in mol/L (M). Enter the amount of substance ā either moles directly, or a mass with its molecular weight ā plus the solution volume, and get the answer instantly.
Enter the moles of solute and the solution volume to get the molar concentration.
What is molar concentration?
Molar concentration is the amount of a dissolved substance per unit volume of solution: the number of moles of solute (n) divided by the volume of solution (V) in litres. Its unit is mol/L, also written as M (molar). A solution labelled 0.5 M contains 0.5 moles of solute in every litre.
When you do not know the number of moles directly, you can find it from the mass of solute and its molar mass, because moles = mass Ć· molecular weight. Substituting that in gives c = mass Ć· (MW Ć V) ā exactly the calculation this tool runs when you choose the mass + molecular-weight mode.
Worked example
Suppose you dissolve 0.25 mol of sodium chloride in enough water to make 500 mL of solution. Convert the volume to litres (500 mL = 0.5 L), then divide: c = 0.25 mol Ć· 0.5 L = 0.5 mol/L, i.e. a 0.5 M solution. Working from mass instead, 11.7 g of NaCl (MW ā 58.44 g/mol) in 0.5 L gives c = 11.7 Ć· (58.44 Ć 0.5) ā 0.4 mol/L.
Molar concentration and molarity
Molar concentration and molarity are the same thing ā both mean moles of solute per litre of solution, expressed in mol/L (M). If you already have a mass and a molecular weight and prefer that framing, the molarity calculator does the identical maths. To then dilute your solution to a lower concentration, use the dilution calculator to solve CāVā = CāVā.
Frequently asked questions
āŗWhat is molar concentration?
Molar concentration is the amount of a dissolved substance per unit volume of solution ā specifically, the number of moles of solute per litre of solution. It is measured in mol/L, also written as M (molar). A 2 mol/L (2 M) solution contains 2 moles of solute in every litre.
āŗIs molar concentration the same as molarity?
Yes. Molar concentration and molarity are two names for the same quantity: moles of solute divided by litres of solution, expressed in mol/L (M). This molar concentration calculator and our molarity calculator perform the identical calculation ā c = n Ć· V.
āŗWhat units does molar concentration use?
The SI-derived unit is mol/L, commonly written as M (molar). Related units include mM (millimolar, 10ā»Ā³ M), ĀµM (micromolar, 10ā»ā¶ M) and nM (nanomolar, 10ā»ā¹ M). This calculator works in mol/L; divide or multiply by powers of ten to convert.
āŗIs this molar concentration calculator free?
Yes. Every calculator on DilutionCalc is free, runs entirely in your browser, needs no sign-up, and never sends your numbers to a server.
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