IIT Kanpur - Indian Institute of Technology

No you cannot get admission in IIT by clearing UPTU Exam.

Hello Prince, it's very nice to hear that you have already fixed the aim of becoming an engineer. As a first step, you need to study really well for next two years with understanding the subject being the theme. Must score at least 75% in 12th and thereafter can apply for B.Tech programme in a reputed college.

First of all, congrats, and you have decided superior colleges.
If interested in computer to for NIT, and if not interested, go for IIT Kanpur. Mechanical and CSE are both the fields of different route. NIT CSE will be good. Moreover, you specified IIIT Allahabad IT, it is again a very good choice. All the options are good. Just see the curriculum and go for your interest.
Good luck.

Generally the cutoff didn't fluctuate and from 3-4 years it wasn't changing .
But no one can say about the gate cutoff for 2018. It will be same or will differ with 1-2 marks.
Most probably it will stay as same .
For choosing any course from particular IIT please ensure that IIT offers the course or not.

For B.Tech from IIT Kanpur, you must qualify JEE Mains and also hold a decent rank in JEE Advanced. Since, you hadn't given JEE Main, I don't think you have any chance of doing that. Also based on your 10+2 marks, you are not eligible for IIT Kanpur, even for NITs and IIITs.

If you are a average student and know your capabilities then you have to work hard, study hard, concentrate and be focus on your studies only and not anything else .
Just go with the concepts of subject of 11th and 12th , practice NCERT as much as you can, Try to solve every question of the book. Go for previous year paper if you want to go for coaching then choose good coaching for the preparation but do not totally depend on it. Do more self study.
You will definitely qualify for 1 attempt in JEE Main.Also if you are of general category then actually you have to study hard.