Molarity Calculator
Solve for molarity, mass, or volume using M = (mass ÷ molar mass) ÷ litres, or switch to dilution mode and solve C1V1 = C2V2.
How to use this calculator
1. Pick concentration or dilution
Use the toggle at the top. Concentration mode works from mass, molar mass, and volume. Dilution mode solves the classic C1V1 = C2V2 relationship.
2. In concentration mode, choose the unknown
Select whether you are solving for molarity, mass, or volume. Fill in the other two fields. Volume can be entered in litres or millilitres.
3. Get the molar mass right
Molar mass (g/mol) is specific to the compound. For example, NaCl is 58.44 g/mol. Look it up or compute it with the linked molecular weight tool.
4. Read the answer
The large value is your solved quantity. The cards below show the formula used and a short breakdown of the calculation.
About molarity
Definition
Molarity (M) is moles of solute per litre of solution. Moles come from mass ÷ molar mass, so M = (mass ÷ molar mass) ÷ volume in litres.
Dilution
Diluting a stock keeps the amount of solute constant while adding solvent. Because moles do not change, C1 × V1 = C2 × V2 — useful for preparing working solutions from concentrates.
Watch your units
Molarity uses litres, so convert millilitres by dividing by 1000. In dilution mode the C1V1 = C2V2 volumes can share any unit as long as both sides match.