As @skieurope said, don’t try to convert your scores- context matters. In one of the countries that we have lived in, an 80/100 was considered an exceptional mark; students with averages in the 70s got prizes.
A better metric is where you fall in your cohort- your school and region. Harvard, Yale, etc are looking for the top few people in a group, whether US or international. Would your teachers say that you are one of the top students - in both an academic and a personal sense- that they have ever taught?