Molar concentration calculator: C = n / V

Molar concentration, more formally amount concentration, tells you how many moles of solute are present per unit volume of solution. It is commonly written C and calculated as C = n/V, where n is amount of substance and V is total solution volume. This calculator solves the relationship in all three directions: concentration from n and V, amount from C and V, or volume from n and C. Common chemistry units are converted automatically, reducing mistakes between micromoles, millimoles, moles, microlitres, millilitres and litres.

The defining relationship is C = n/V. IUPAC defines amount concentration as amount of substance divided by the volume of the mixture. In laboratory work it is commonly expressed in mol/L, while the coherent SI form is mol/m³.

The same equation rearranges to n = CV when concentration and volume are known, or V = n/C when amount and concentration are known. The calculator detects the empty field and selects the appropriate algebraic form.

Internally, values are converted to mol/m³ for concentration, mol for amount and m³ for volume. Results are then converted back to the selected display unit. This makes calculations such as 250 mmol in 500 mL consistent without manual scaling.

Supported units include µmol, mmol and mol for amount; µmol/L, mmol/L, mol/L and mol/m³ for amount concentration; and µL, mL, L and m³ for solution volume. A useful equivalence is 1 mol/L = 1000 mol/m³, while 1 mmol/L = 1 mol/m³.

Molar concentration should not be confused with mass concentration. g/L is mass per volume, while mol/L is amount of substance per volume. Converting between them requires the solute molar mass M and the relation n = m/M.

This calculator complements the dilution calculator. C = n/V describes one solution state directly, while C₁V₁ = C₂V₂ connects two states during a dilution where the relevant solute amount is conserved.