I am getting 78 marks in jee mains April what should be my rank?

Hi, your rank lies between 90,530-110530.Your expected percentile is between 88.3-90.3. Though this is just your predicted percentile and it may vary as your percentile is calculated after normalisation that means, after considering various factors such as the difficulty level of your paper in comparison to the others.

If you want to know which colleges you can get on the basis of your score, you can check out the following link-

https://engineering.careers360.com/jee-main-college-predictor
All the best!