Molarity Calculator
Work out the molar concentration of a solution, or find the mass, moles, or volume you need. Choose what to solve for, enter the other values, and calculate.
| Solve for | |
| Molarity | |
| Mass | |
| Molar mass | |
| Volume |
Leave the field you are solving for blank (it will be calculated). Molar mass is the mass of one mole of the substance (for example, NaCl ≈ 58.44 g/mol).
Result
Your result will appear here.
Formulas
Molarity (M) = moles of solute / litres of solution
Moles = mass / molar mass
Combined: M = mass / (molar mass × volume) (with mass in g, molar mass in g/mol, volume in L)
Assumptions and notes
- Volume means the final volume of the solution, not just the solvent added.
- Units are converted automatically (mg↔g↔kg, mL↔L, mM↔M) before calculating.
- Results are numerical estimates; for lab work, use precise measurements and appropriate significant figures.
How it works
Molarity (M) measures concentration: moles of solute per litre of solution.
Formulas
- M = n / V, n = mass / molar mass, and mass = M × V × molar mass.
Worked example
1.0 L of 1.0 M NaCl (58.44 g/mol) requires 58.44 g, made up to 1.0 L total solution.
Assumptions
- Use final solution volume and consistent units. For lab/medical work, confirm with proper procedures.
Estimate for general information only. For laboratory or medical use, follow proper procedures and confirm measurements.
How to use the Molarity Calculator
It takes a few seconds, and every figure is calculated in your browser.
- Choose what to solve for.
- Enter the molarity.
- Enter the mass.
- Enter the molar mass.
- Enter the volume.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Molarity Calculator — frequently asked questions
What formula does the Molarity Calculator use?
Molarity (M) = moles of solute / litres of solution Moles = mass / molar mass Combined: M = mass / (molar mass × volume) (with mass in g, molar mass in g/mol, volume in L)
How does the Molarity Calculator work?
Molarity (M) measures concentration: moles of solute per litre of solution.
What assumptions and limitations should I know about?
Volume means the final volume of the solution, not just the solvent added. Units are converted automatically (mg↔g↔kg, mL↔L, mM↔M) before calculating. Results are numerical estimates; for lab work, use precise measurements and appropriate significant figures.
Can you walk through a worked example?
1.0 L of 1.0 M NaCl (58.44 g/mol) requires 58.44 g, made up to 1.0 L total solution.
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.