Free · General chemistry calculators ⚛️

Mass Concentration & Molar Concentration

Convert positive mass-per-volume concentration to amount-per-volume concentration using the solute molar mass.

Formula & worked example
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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

Mass concentration 10 g/L and molar mass 50 g/mol correspond to 0.2 mol/L, or 200 mM.

Molar concentration = mass concentration / molar mass

Worked example

Enter these known values and leave the other values blank.

Solute molar mass: 50 g/mol
Solute mass per solution volume: 10 g/l

Amount concentration: 0.2 M

Assumptions and limitations

Molar mass and both concentrations are positive. Specify the chemical entity and hydration or formula state represented by the mass.
Both concentrations refer to final solution volume, not the starting solvent volume. Molar concentration is also called molarity.
A molar mass entered in g/mol has the same numerical value in kg/kmol or lb/lb-mol. These are molar-mass units, not mass concentration.

Common questions

Is 1 mg/mL the same as 1 g/L?

Yes. Both equal one gram per liter, but neither determines molarity without molar mass.

Does this convert a mass percentage directly?

No. A mass fraction needs solution density to become mass per volume before this conversion.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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