The IB is considerably more difficult than the A levels. In the IB, students must study six more subjects, while A-level students study three subjects. With such a workload, it's no surprise that many IB students end up with relatively low grades (between 24 and 30 points). Generally speaking, the IB will take longer than levels A.
But, in terms of getting you to college, which one is the best? Well, I'd say it depends on what kind of student you are and what goals you have. Don't you know what I'm talking about? Then, keep reading and I'll explain which of these courses is right for you. In terms of exams alone, the APs were slightly easier compared to the IB exams, but the A-level and IB exams for the STEM NS were quite similar, with A-levels more academically rigorous in a few and IB exams in the other. While IB Further Math consists of linear algebra and geometry, A Level Further consists of Linear Algebra-Calculus-Precalculus.
Only from a temporal perspective, IB's are more demanding of their students on a daily basis. Universities typically request specific grades in different A-level subjects, while IB students usually set an overall scoring goal. A typical A-level student will study 4-5 subjects at the AS level, then 3 in year 13, an IB Diploma student will have to study 6 until the end. In effect, this means that all IB Diploma students will study subjects in the arts and sciences, while A-level students can focus on a smaller group of subjects in one area (if they wish).
For this reason, the Extended Essay, Theory of Knowledge and Creativity, Action and Service segments of the IB require additional work. I will be more than happy to discuss and give realistic advice about the IB and the value, complexities, etc. You only have to take 3 subjects at level A, while in the IB you have to take six; math at levels A is nowhere near comparable to mathematics HL, and more levels of math A are also not CLOSE to others mathematics HL. If getting the best grades is a priority for you and you're self-motivated, you'll probably end up studying as hard as an IB student.
So, whether you're studying levels IB or A, you'll usually only have three subjects that will help you meet specific entry requirements. If you don't necessarily want to go to a university in the UK, the IB is probably the best option. There are three additional points awarded based on ratings in the EE, CAS and ToC parts of the IB. The IB requires organization and independence from the beginning of the course; since all six-subject exams are taken at the end of the course, it is simply not possible to take the weeks leading up to the exams.
While A-levels have their own difficulties, the extra hours required to complete the IB really take their toll. The IB's expanded essay and epistemology elements add additional flavor and rigor that prepare them well for university.