How do you define or declare that a film is a flop or disaster. There are many permutations and combinations which occur when a film completes its full business run. And categorizing a particular movie as a hit or flop is subject to different factors.
This is largely applicable for big star films because the stakes are high and pressure to recover the investment is also high. The trade pundits say there is no quantifiable measurement but the closest they can decipher is investment versus returns from the movie.
So, it all depends on how much money has been spent on making the movie, for what price it was sold to the exhibitors and finally, how much money did the exhibitors make. In the case of recent release Katamarayudu, the film garnered a whopping 62 crores in its full run and yet it is a flop. Reason being, it was sold at a premium of 72.5 crores and could have made it safe only if it got 80 crores. Hope the equation is clear now.