Skip to main content
Calculator Answers

Molarity Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

Molarity, or molar concentration, is a measure of the concentration of a solute in a solution, defined as the number of moles of solute dissolved per liter of solution. A molarity calculator computes molarity, solute moles, or solution volume based on the formula M = n / V. When the solute's molar mass is provided, the tool also computes solute mass from the relationship n = m / M. Chemists and students use this calculation to prepare solutions of specific concentrations and to perform stoichiometric analysis in chemical reactions.

Pick what you want to find and the calculator returns the value using M = n / V (and n = m / Mₘ for mass mode). Volume can be entered in liters or milliliters. The result panel shows the formula with your values plugged in.

See also: Dilution Calculator, mg to mL Calculator Using Concentration, and Percent Yield Calculator.

Quick Answer

Calculate molarity, moles, volume, or mass of a solution. Enter any three known values to find the remaining variable.

What to compute

mol

Volume unit

Reminder

Molarity is concentration in moles of solute per liter of solution. The relationship is M = n / V, with V always in liters. For mass, use m = n × Mₘ, where Mₘ is the molar mass of the compound (g/mol).

Educational chemistry only. Not lab dosing, safety, or medical advice.

Result

Molarity

0.5 mol/L

FormulaM = n / V = 0.5 mol / 1 L = 0.5 mol/L
Moles n0.5 mol
Volume V1 L
Molarity M0.5 mol/L

For volume conversions between L and mL or other volume units, see the volume converter. For mass unit conversion (g, kg, oz), see the weight converter.

Was this helpful?

Examples

0.5 mol NaCl in 1 L solution

0.5 M

0.1 M × 250 mL

0.025 mol

1 mol at 0.2 M needs

5 L volume

0.25 mol of glucose at 180 g/mol

45 g

How it works

The molarity definition gives a direct relationship between three quantities. Solve for any one given the other two.

Molarity · M = n / V

Moles from mass · n = m / Mₘ

n is moles, V is volume in liters, m is mass in grams, Mₘ is the molar mass in grams per mole.

Related chemistry and unit calculators

Related Calculators

More tools from Education

Dilution CalculatorSolve M1V1 = M2V2 for any of the four variables, find the dilution factor, and plan simple serial dilutions. Supports mL and L. Educational chemistry only, not lab or dosing advice.mg to mL Calculator Using ConcentrationConvert an amount in milligrams to a volume in millilitres using the concentration printed on the product, or work backwards from a volume. Concentration is required; mg and mL do not convert directly.Percent Yield CalculatorCalculate percent yield, actual yield, or theoretical yield using % yield = actual / theoretical x 100. Supports grams, kilograms, milligrams, and moles. Educational chemistry only.pH CalculatorConvert between pH, pOH, hydrogen ion concentration, and hydroxide ion concentration using pH = -log10[H+] and pH + pOH = 14 (at 25 C). Educational chemistry only.

Frequently asked questions

Molarity is concentration measured in moles of solute per liter of solution, written mol/L or M. A 1 M solution has one mole of solute dissolved in enough solvent to make one liter of solution.

Use n = m / Mₘ, where m is the mass of solute in grams and Mₘ is the molar mass in g/mol. The molar mass is the sum of the atomic masses of every atom in the compound. The calculator's mass mode reverses this for m given n and Mₘ.

Convert to liters first: 1,000 mL = 1 L. The calculator includes a unit toggle so you can enter either L or mL and the formula uses liters internally.

No. Molarity is moles of solute per liter of solution (volume-based, sensitive to temperature). Molality is moles of solute per kilogram of solvent (mass-based, temperature-independent). For most intro chemistry, molarity is what is meant.

Dilutions use M₁V₁ = M₂V₂. This calculator handles the M, n, V, m piece. For dilution arithmetic, use the relation directly: solve for the unknown and plug in.

No. The calculator is an educational tool that performs the standard chemistry arithmetic. Do not use the output for laboratory preparation, dosing, or any safety-critical decision; consult an instructor or a vetted procedure.