Hello,

For JEE Mains-

There is no age limit. However, they have to pass 10+2 or equivalent exam in 2018 or 2019.

Candidates appearing for 10+2 or equivalent exam in 2020 are also eligible to apply.

Number of attempts

JEE Main candidates can participate in the entrance exam for 3 consecutive years. The exam will be conducted twice a year, they may appear in both the attempts. The attempt for an academic year will be considered as One.

For more details, consider going through following link-

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

For JEE Advanced

There's no age limit for JEE Advanced as well, however a maximum of two times in two consecutive yars can be attempted by candidates.

The candidates should have appeared for 12th standard (or equivalent) qualifying examination in 2019 or 2020, for the first time. However, if the result is declared for the academic year 2017-18 after June 2018, then the candidates of that board who appeared for their 12th standard qualifying exam in 2018 will also be termed eligible for JEE Advanced 2020, if they also meet the other eligibility criteria.

For more details, consider going through following link-

https://engineering.careers360.com/articles/jee-advanced-eligibility-criteria