what is the scaled score? how do they calculate score in CAT?how Can i use this method to calculate my score? method?

Scaled score is a way to make changes in your score according to your accuracy rate and standard deviation.

First thing you need to know that changes due to scaled score turns out to be minor changes and there is no fixed way of finding it without having scores of all the students because we cannot find standard deviation. So it is beyond our limits.

Anyway we can't even predict our exact percentile without marks of all the students. There is a possibility that all the percentile predictor sites can fail still to just get an idea or range of your predicted percentile you can check out those sites and don't worry about the scaled score.

Still if you want to know a little more about scaled score you can check here:

http://www.careeranna.com/articles/scaled-score-cat/

It's better to get an idea of your raw percentile, apply for the colleges other than IIMs which you find right for yourself and start preparing for second round of interview and WSAT instead o worrying about scaled score.

All the best!!