Hi dear,

Your gate score is 831.with this score you will definitely get IIT Bombay but you have low chance of getting IISC Bangalore.You have a chance to get most of the IITs. You can check here other college's cutoff

https://www.google.co.in/url?sa=i&source=web&cd=&ved=2ahUKEwjDo4v9yI3hAhVXWH0KHT37AGwQFjAMegQIAhAB&url=https%3A%2F%2Fengineering.careers360.com%2Farticles%2Fgate-cutoff%2Famp&psig=AOvVaw1ZOk9vJPd2mX2CXqPnjkg7&ust=1553063085204209

Hope it helps