Hi Neville-

I was just going to post a question about the many calculus courses at KA. I did a very brief survey and there is some overlap between them. The biggest issue I see is that the progression seems to be a bit different depending on which course you start with, although it looks like the same material gets covered -- for the most part -- in all the different courses.

To your question; yes, as much algebra as you can get your hands on. The big topic you will need is trigonometry. The calculus courses use trig almost from the very start, so if you don't have a handle on it, it may trip you up when a calculus lesson involves a trig function of some kind. There is a pre-calculus course on KA, and something else called "get ready for calculus"  I think. I highly recommend that you work thru those units and make sure that you have a reasonable understanding of the material. (I tend to follow Sal's advise and work towards mastery before moving on.)

I see no reason why you can't start with the AP/AB 2017 course. It seems comprehensive but you can always look at one of the other courses to see if there are any lesson topics that you may want to cover. I found the AP/AB course well-structured, and again, there is quite a bit of overlap between the courses. AP/BC is a bit more detailed/rigorous, but if you have AP/AB under your belt you shouldn't have any trouble. (I'm giving you my opinion as a end-user, not as a math instructor or curriculum developer.)

One of the great things about KA is that you can choose how intense you want your learning experience to be and at what pace to take it. 

Good luck with your studies.

Thanks Kevin, incredibly useful advice. Much appreciated.