For your odds of at least one top 20 school, multiply (1-estimated_chance) together for all the schools, then do 1 - that number. For you, odds of at least 1 top 20 school (just based on this calculator) are about 99.99999997%.
nb This pretends that each application is totally independent of the others. Take that assumption at your own risk.
Comments
https://7sage.com/admissions/predictor/
For your odds of at least one top 20 school, multiply (1-estimated_chance) together for all the schools, then do 1 - that number. For you, odds of at least 1 top 20 school (just based on this calculator) are about 99.99999997%.
nb This pretends that each application is totally independent of the others. Take that assumption at your own risk.