Why are percentiles for SAT Subject tests so different for the SAT?

I feel it is relatively easy to be in top 10% for the plain SAT
but to be in the top 10% for SAT subject tests would mean getting no more than a couple wrong.

What’s up with that?
This is really stressing me out as I don’t know anything besides AP Chem topics for the Chem SAT tomorrow

Relatively few colleges require/recommend Subject Tests, and those that do tend to be the most selective colleges. As a result, the students that tend to take the Subject Test are a self-selected group of high achieving students. That is why the percentiles in many of the subjects is depressed.

Having said that, no AO is sitting on the floor cross referencing scores to percentiles, so don’t worry about it if your Subject Test scores are in line with your SAT scores.

@skieurope So you think basically like a 750 on Chem would match 1500+ SAT?

Recognizing that there is a whole lot more that goes into an application packet than scores, yes, that example works. @AimingTop50