As a broad approximation from the results of The Computer Language Benchmarks Game, Racket is 5 times faster than Python and 5 times slower than C. https://benchmarksgame-team.pages.debian.net/benchmarksgame/... (I can't find a direct comparison of Python-vs-Racket in the site.)
The difference with Python is probably bigger in programs with a big numeric part, and much smaller in programs with a lot of string. Take that number just as a general guide, not as a precise scaling factor.
Racket vs Python is a "common" comparison. I write the same comment once or twice per year :). (Probably because both are high level and have the batteries included. (The syntax is slightly different :) ))
