The best universities in both countries recognize the International Baccalaureate (IB), Advanced Placement (AP) and A Level curricula. However, there is a level of familiarity that universities might have with their own country's curriculum. This doesn't mean you won't be entering American universities with A or IB levels, or vice versa. It's important to consider which curriculum is the most suitable for you and your goals. If you want to challenge yourself academically, the IB would be the most rigorous.
Levels A, on the other hand, give you a level of flexibility while still challenging you and allowing you to get the best score due to the structure of your exam. If your school doesn't offer an international curriculum, taking part time AP classes can help improve your college admissions profile. All US universities accept the IB Diploma now and know all its requirements and value. Most US universities offer credit for IB courses (it's worth applying for), and many offer college credit for AP courses as long as exam scores are high. As mentioned above, some can also give credit for A levels.
That credit may allow an incoming freshman to skip the basic course of the 500-person survey taught by a graduate student, or reduce expenses in one semester (if a student has enough credit to skip 3 or 4 of the total courses required to earn a degree).The IB Diploma is an alternative to A-levels for students aged 16 to 18 and does not require any specific preparatory class work, so it can be done directly from the GCSE. It offers a broad curriculum composed of six subject groups: students usually study three at a higher level and three at a standard level. None of them, levels A, AP or the IB Diploma, are better than the others. Everyone is perfectly fine for college and worth it in the most objective way. You will learn a lot, whichever one you choose.
Levels A, IB, and AP are academically challenging and are considered the highest high school options students can take. As an IB alumni, I can certainly attest to the fact that the IB Diploma really develops who you are as a high-achieving student. It's a video I found on YouTube that really does a good job of identifying the differences between the AP and the IB Diploma on a summarized scale. The British University and College Admissions Service (UCAS) has developed a fee system that helps compare IB scores with equivalent A-level grades. BUT, for such a specialized field (medicine), some UK universities would want the applicant to have done biology, chemistry and physics at level A, which cannot be done at level IB. The IB Diploma is suitable for students who want to maintain breadth in their choice of subjects and who are willing to work hard in a structured environment and tolerate tackling weak areas. As university admissions officers increasingly care about students with a particular skill set, Fergus Rose, Promotion Director for ACS International Colleges, elaborates on the argument that the IB Diploma better prepares students for university and the rest of the world.
New research reveals disparity between qualities fostered in A-level and IB students. Occasionally, schools advise parents that their child should take the GCSE if he wants to go to a UK university, insisting that UK universities want to see British test results and will not accept international school assessments (transcripts) or internal certificates from, by example, the IB Middle Years Program or an American High School. We commissioned research from the IB and the IB Association of Colleges and Colleges (IBSCA) to survey 80 university admissions officers in the UK (representing almost half of UK universities) to find out which entry degree they preferred. In any case, it is important to consult with your high school's college and career counselor - this is where many US councilors will not know about UCAS applications for UK universities, and British councilors may not know about strategies for US applications (scheduling SAT exams, teacher referrals, college visits and interviews, application deadlines, etc.).I think that if you apply yourself and keep up to date with everything IB has to offer, you'll feel 100% worth it in the end.