Help! how long does sixth form reference take??

So I submitted my sixth form applications today and just realised that I need my reference letter form my form tutor by friday so Im panicking. How long does these reference usually take if my form tutor has already written once for other schools?

If they've already written one for you to present to other schools, then it should take very little time. Assuming, that is, this particular sixth form don't mandate that it has some unusual format or contain some information which isn't already present.