How much marks or percentile is required for getting admission in top 5 IIT?

You need to qualify  jee advance to get admission in iit. And for top 5 iit you need to score under 1k rank in case if you have category then maybe a little lesser rank may also get a seat in top 5 iit.

Also it's very easy to predict college on careers360 by clicking on the link mentioned below its very user friendly and very helpful

https://engineering.careers360.com/jee-main-college-predictor

Feel free to comment if you have any doubt
Good luck