IIT stands for the Indian Institutes of Technology, which are the most elite tech schools of the country. They admit students based on the JEE Advanced and Gate supposedly the toughest exam in the world. They have world class facilities and infrastructure. Placements are great and companies pay hefty packages to recruit IITians because they are perceived to be the best engineers in India and possibly the world.

NIT stands for National Institutes of Technology. These we formerly called Regional Engineering College. Though not as good as IITs, they are also excellent Institutes for Engineering. They have a grant money lesser than IITs which in most cases results in a lower level of infrastructure and facilities as compared to an IIT. They admit students from the JEE Main and Gate.

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