Dear candidate

With 81 percentile your score will be around 50 or something so with that score your sc category wise rank will be around  3000 or something so that rank you can get into Electrical engineering and civil engineering branches at NITs so, vist the below mentioned NIT cutoff trends link to check in which NIT what branch  you can get so, check it out and find out

Visit the below mentioned link to predict your rank

Visit the below mentioned link for top NIT cutoff trends

https://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

Visit the below mentioned link to predict what colleges you can get with your overall percentile in JEE MAINS you can also find what NITs you can get into by this JEE MAINS college predictor tool

Hope this Information is helpful