V1 = Volume of the 1st solution , V2 = Volume of the 2nd solution , S1= Strength of the 1st solution, S2= Strength of the 2nd solution
Titration is simply the slow addition of one solution of known strength (concentration) to another solution of unknown strength until neutralization. This neutralization is often indicated by a color change of an indication or by the change in slope in a conductometric plot of conductivity vs volume of solution added. Thus knowing the values of the volumes of both the solutions and the value of strength of any one of the solution will lead to the unknown value of strength of the unknown solution. You can use this calculator ( online tool) for such titrational calculation.