How much does the TOEFL score matter?

I’m applying to MIT, Stanford, Harvard and Caltech. I was wondering how much my TOEFL score, as an international student, matters given that it is above the requirement (which is around 100). Do admission committees give more “credit” to a slightly higher score (say 115-120 instead of 100)? Or they just check that the candidate has at the least the minimum required?
I’m also taking the SAT and the SAT Subject tests, for which there’s not a requirement and I know that the higher the score, the better the chances of getting in.

“they just check that the candidate has at the least the minimum required” – rather this. But keep in mind that most of the international students applying to elite universities will have higher and much higher than required scores. To get a sense of the scores by successful applicants, check out the individual threads on these schools in the Colleges and Universities subforums.

Penn published the average TOEFL iBT score of their accepted students a few years ago, and it was 113. The minimum requirement was 100.

Since TOEFL scores seem highly correlated with verbal SAT scores (applicants who struggle on the TOEFL usually struggle on the SAT as well), it’s hard to tell statistically if colleges use the TOEFL requirement as a pass/fail criterion, or if they pay attention to the actual number.

That being said, international students whose English is “good enough” usually catch up very quickly once they arrive in the US. Colleges know this. Furthermore, the universities you named have their pick of the best and brightest applicants from all around the world. I assume that they would be much more concerned about your accomplishments (e.g. many international students at Caltech and MIT have awards from international science competitions) than about whether your TOEFL score was 115 or 105.

^B@r!um is right: once you’ve hit the magic number (and 100 is quite high), they will look at your other tests, and for those the higher, the better.