How to Calculate Pay for Defence Personnel? Formula for Fixation of Pay Formulae for Fixation of Pay from 3rd CPC to 4th CPC If 20% x of B.P (3rd CPC)Value is less than 75 then B.P+ D.A + A.D.A + ad hoc DA + IR-1 & IR-2 + 75 = 4th CPC Basic Pay Otherwise, B.P + D.A + A.D.A+ ad hoc DA + IR-1 & IR-2+ + 20% of B.P= 4th CPC Basic Pay Formulae for Fixation of … [Read more...] about How to Calculate Pay for Defence Personnel? Formula for Fixation of Pay