Hi

One  can give JEE Mains entrance  examination  for a maximum of  3 consecutive years  starting from the year of passing 12th board examination.

Now,

JEE Main entrance examination  is conducted twice a year i.e January and April session.

So,  the maximum number of attempts for jee mains entrance examination

= 2 times *3 years

=  6 attempts in total

Now,  if you have passed your board examination this year i. e 2020 and even if you don't appear for JEE Mains January and JEE Mains September session of 2020 , you will still lose your two attempt and will have only four more attempt left i. e both the sessions of JEE mains 2021 and 2022

Thank you