Moles of solute and solution volume in liters—molarity M (mol/L).
Here M = moles ÷ liters (six decimals). Both inputs must be positive; solvent volume vs solution volume distinctions are not modeled beyond “liters” as typed.
This calculator uses plain decimal numbers. If a result looks wrong, check whether you used a comma instead of a dot (or vice versa) where the field expects one.