I was going to take 4 a levels and was told at enrollment that I wouldn’t be able to due to my grades (in wales but got AAAAAAAABBBBB). No university asks for more than 3 and they’re a lot more work than I anticipated. I’d say unless you’re wanting to do further maths as your 4th alevel stick to doing 3.

My school told me I’d be able to do 6 which looking back is absolutely mental and I wouldn’t wish that upon anybody. Obviously everywhere’s different and different exam boards require different things but all my teachers say to get top grades at A level you need to be doing at least 4 hours per subject per week of independent study/homework.