Hi Ansh,

GATE score is not a necessary requirement for PhD entry into IITs. PhD admissions are undertaken two times a year: one for the July-Dec semester and the other for the Jan-May semester. There are generally two steps for PhD admissions :

1. You have to apply individually to every IIT on their website. Once you apply, they will generate a shortlist based on the applications and their number of requirements.
2. The shortlisted candidates will be called for Written Test/ Interview at the respective IITs.

Once you qualify both of the above steps, you will be asked for guide preference and your area of interest. If the vacancies and the interests match, you will get the admission.

Returning to your question, there is a direct PhD program that allows you to do Pht with GATE Score.

For the IIT Kanpur Gate Score > 720 ( with excellent academics) and GATE Score >750 (with good academics )

Note: The cutoff varies every year with a +-(20 ).Considering the fact that the number of seats in PhD changes depending upon the availability of vacancies under a professor, sponsored projects, the cutoff does not maintain a regular trend.

Hope this information was useful for you.

All the best.