Can I get admission to IIM Calcutta with an 80 in 10th, 99.85 in 12th, and 98 in graduation?

IIM Calcutta focuses on CAT rather than 10th/12th/graduation to give you PI calls. Then, during the selection stage, IIM C prioritizes PI performance over all other factors. So, without a doubt, your academic results are excellent and will aid you in the admissions process (though relatively low). So, if you want to get into IIM C for MBA, you should focus on getting a higher CAT percentile and excellent PI preparation and performance. 

If you have academic or gender diversity work experience, or if you are from the EWS/PwD/NC-OBC/SC/ST category, the process will be sped up.