JEE Main will be conducted 4 times this year 2021 in February, March, April and May. However, it depends on the candidate how many attempta he wishes to make. The highest net percentile score among attempts will be considered for Ranking purposes. JEE Main Rank is used for admission to various NITs, IIITs, GFTIs as well as certain State Engineering Colleges and Private Institutes.

For more information do follow the link below

https://engineering.careers360.com/articles/jee-main-exam-dates

Hello student ,

As of last year, the engineering entrance examination was only conducted twice a year for admissions into undergraduate engineering courses. The Education Ministry has announced that the exam will be conducted four times a year from the upcoming academic session. So JEE Main 2021 examination will be conducted in February, March, April, and May this year. The first attempt of the exam will be from February 23 to 26, 2021. The last day to register for the entrance exam is January 16.

Hope it helps !