Adaptive Conditional Probability Estimator (ACPE) technique is applied to fixed width booth multiplier .It is applied based on the theory called conditional-probability theory. The ACPE can be easily applied to more than 16bit Booth multipliers for achieving a higher accuracy performance. The ACPE provides varying column information to adjust the accuracy with respect to system requirements. The area and power can be reduced to considerable amount compared with the existing methods. Hardware complexity is reduced and power saving can also be achieved. The truncation errors have been hugely reduced. This ACPE Booth multipliers can also be applied to the two-dimensional cosine transforms to demonstrate the performance of real time applications.