Molarity Calculator

Calculate molarity, moles, volume, or mass for chemistry solution preparation.

A molarity calculator determines the concentration of a solution in moles per liter from the solute mass, molecular weight, and solution volume.

Select what you want to solve for (molarity, moles, or volume), then enter the two known values. The calculator uses the formula M = n / V to find the missing quantity.

Examples

Find molarity: 0.5 mol in 0.25 L

M = 0.5 / 0.25 = 2.0 M (2.0 molar solution).

Find volume for 1M solution with 0.1 mol

V = n / M = 0.1 / 1.0 = 0.1 L (100 mL).

Frequently Asked Questions

What is molarity?
Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. A 1 M solution contains 1 mole of solute in 1 liter of solution.
What is the difference between molarity and molality?
Molarity (M) is moles of solute per liter of solution. Molality (m) is moles of solute per kilogram of solvent. Molality is temperature-independent because mass does not change with temperature, while volume (and thus molarity) does.
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Quick Tips

  • Always measure volume of the final solution, not the solvent alone — adding solute changes the total volume.
  • For dilutions, use M1V1 = M2V2 to quickly calculate the required volumes.

A molarity calculator determines the concentration of a solution in moles per liter from the solute mass, molecular weight, and solution volume.

How to Use This Calculator

Select what you want to solve for (molarity, moles, or volume), then enter the two known values. The calculator uses the formula M = n / V to find the missing quantity.

Understanding the Formula

M = n / V, where M is molarity (mol/L), n is moles of solute, and V is volume of solution in liters. Rearranged: n = M x V, V = n / M.

Examples

Find molarity: 0.5 mol in 0.25 L

M = 0.5 / 0.25 = 2.0 M (2.0 molar solution).

Find volume for 1M solution with 0.1 mol

V = n / M = 0.1 / 1.0 = 0.1 L (100 mL).

Frequently Asked Questions

What is molarity?

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. A 1 M solution contains 1 mole of solute in 1 liter of solution.

What is the difference between molarity and molality?

Molarity (M) is moles of solute per liter of solution. Molality (m) is moles of solute per kilogram of solvent. Molality is temperature-independent because mass does not change with temperature, while volume (and thus molarity) does.

Assumptions & Limitations

  • Assumes the solute is fully dissolved and the solution is homogeneous.
  • Volume refers to the total solution volume, not just the solvent volume.
  • Does not account for dissociation of ionic compounds in solution.