MasterTool

Molarity Calculator

Calculate molarity instantly in your browser — the published formula, worked locally with no data sent anywhere.

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What this tool does

Calculate molarity instantly in your browser — the published formula, worked locally with no data sent anywhere. Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.

How to use the Molarity Calculator

  1. Enter or select solve for.
  2. Enter or select moles of solute (mol).
  3. Enter or select solution volume (l).
  4. Enter or select molarity (mol/l).
  5. Enter or select solute formula (for the grams conversion).
  6. Read the calculated result; change any measurement to compare alternatives.

Formula

molarity M = moles of solute ÷ litres of solution. Rearranged: moles = M × V and volume = moles ÷ M.
solve
Solve for
moles
Moles of solute (mol)
volume
Solution volume (L)
molarity
Molarity (mol/L)
formula
Solute formula (for the grams conversion)

Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.

Worked example

For molarity calculator, the following measurements illustrate the exact method: Solve for: molarity; Moles of solute (mol): 0.5; Solution volume (L): 0.5; Molarity (mol/L): 1; Solute formula (for the grams conversion): NaCl.

Inputs

  • Solve forMolarity
  • Moles of solute (mol)0.5
  • Solution volume (L)0.5
  • Molarity (mol/L)1
  • Solute formula (for the grams conversion)NaCl

Result

  • Molarity (mol/L)1
  • Millimolar (mmol/L)1,000
  • Grams of solute for this amount (g)29.22
  • Solute molar mass (g/mol)58.44

Results explained

Molarity (mol/L)
Molarity (mol/L) from the formula above. Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.
Millimolar (mmol/L)
Millimolar (mmol/L) from the formula above. Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.
Grams of solute for this amount (g)
Grams of solute for this amount (g) from the formula above. Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.
Solute molar mass (g/mol)
Solute molar mass (g/mol) from the formula above. Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.

Frequently asked questions

molarity M = moles of solute ÷ litres of solution. Rearranged: moles = M × V and volume = moles ÷ M.

Volume is the volume of the finished solution (solute + solvent mixed), not the solvent alone — that distinction is what separates molarity from molality. Temperature changes molarity slightly because solutions expand.

Every field is labelled with its unit — enter values in exactly the labelled unit and read the result in the labelled output unit. Fields with a unit symbol also support the site-wide imperial/metric switch, which converts before the formula runs.

It uses double-precision arithmetic and the published constants and formulas named on this page. The last displayed digit may be rounded, and real conditions can differ from the idealized model described in the assumptions.

Yes. Every calculation runs entirely in your browser; nothing you enter is uploaded, stored or shared.