To calculate the volume of a definite solution required to prepare solutions of other normality, the following equation is used:

*N1V1=N2V2*

where,

N1=initial normality and N2=normality of the new solution,

and V1= initial volume and V2= volume of the new solution.

The normality equation is commonly used to calculate the normality of solutions after dilution. The above equation is also called as dilution formula because it helps in calculating the volume of the solvent required in diluting a concentrated solution. The same equation holds good for calculations involving molarity (M).