Chance me for MIT/Ivies

SAT Score: 1580
Edexcel GCSE/IGCSE Results: 8 Subjects taken, achieved a level 9 in all.
4 A Levels taken, 4 A* Predicted Grades.
Achieved highest international mark in 2 subject (ICT and Physics), and achieved a national highest mark in Religious Studies.
Extracurriculars: Achieved third place in a national level science and engineering quiz.
Won around 11 cross country/ middle/ long distance races (school level).
Let’s say I also have some stellar recommendation letters.
What would you say are my chances?

You are in the group of students that meet all of the admission hurdles which are then selected based on personal attributes, demographics, class mix, etc.

Each of those schools could fill the slots that are left, after legacy, athletes, etc., three or five times over, or more, with qualified students. So probably 15-25% at each school.

Your stats are great. My understanding is that the overall acceptance rates for international students at MIT and at the top ranked Ivy League schools is somewhere around 1%. I would wildly guess that your chances might be twice this, but still in the low single digit percentages.

You obviously have done exceptionally well in high school. I expect that you will probably continue to do very well regardless of where you end up, whether it be in your home country, the US, or somewhere else.

I had assumed the marks I didn’t understand were IB-related, with which I’m not familiar, as you said nothing about being outside the US.

If you are international, the acceptance rate is 3.1%, just under half of US applicants, so adjust the numbers above accordingly. I also suspect, though I have no supporting data, that the international pool is slightly more competitive.