Here's the fact that changes how most of this guide applies to you: the CAO's points system is built for students finishing the Irish Leaving Certificate, and most US applicants don't get ranked in it at all. Applicants from outside the EU generally apply directly to the university, on that university's own admissions process, not through CAO's points-based ranking.
What Do CAO Points Mean?
CAO points are a score out of 625, built from your best six Leaving Certificate subjects -- each Higher Level grade is worth a fixed number of points (a H1 is worth 100, down to a H5 at 56), with a 25-point bonus for Higher Level Maths at H6 or above. Courses set a minimum points requirement each year based on demand, and the CAO offers places to the highest-scoring applicants first. As a US applicant, though, this number almost never applies to you directly -- see why below.
What the CAO actually is, and who it's really for
The CAO (Central Applications Office) is Ireland's centralized system for undergraduate admissions, built around a points scale derived from the Leaving Cert: each Higher Level grade earns fixed points (a H1 is worth 100, down to a H5 at 56), your best six subjects count toward a 625-point maximum, and a 25-point bonus applies for Higher Level Maths at H6 or above. When a course has more qualified applicants than places, the CAO makes offers to the highest-scoring applicants first, then keeps offering further down the list as places open up. The normal CAO closing date is 1 February at 17:00, with a later restricted deadline of 1 May for certain courses -- but again, that whole calendar is built around Leaving Cert-track applicants, not the direct-entry route most US students use.
How a US applicant actually applies
Rather than being scored on the Leaving Cert points scale, a US applicant typically applies straight to the university's own international-admissions office, on that university's own deadline and criteria -- verify this per school rather than assuming it's universal. Trinity College Dublin's own US-applicant page, for instance, makes no mention of the CAO at all: it directs US applicants to Trinity's own "How to Apply" process, with published test-score minimums of SAT 1250-1400 across two sections (no section below 500) or ACT composite 27-32, plus a GPA/transcript-based alternative path when test scores aren't submitted. Other Irish universities publish similar direct international-applicant routes with their own criteria -- University College Dublin, for example, accepts either the SAT or ACT with no preference between them, considered alongside the rest of a US applicant's record rather than required outright for every course. Don't assume one university's process describes another's; check your specific target school's own international-admissions page. See our full breakdown of the three real, confirmed pathways at Trinity, UCC, and UCD for the specific GPA and test-score floors at each -- including how UCC's Band system works.
If you're applying with the IB Diploma specifically, the CAO does publish a real, official IB-to-points conversion table -- but per Trinity, UCD, and DCU's own pages, it's scoped to EU/UK-fee-status applicants, not US ones. See how Irish universities actually score the IB Diploma for US applicants for the direct, non-CAO figures those three schools use instead.
You still pick a specific course, not an undeclared major
Even outside the CAO's points system, the course-selection rule from How UCAS Actually Works still applies here: a US applicant to an Irish university applies to a specific named course -- Economics, Chemical Engineering, whatever it is -- not to the university generally with room to explore first. See Course Selection for how binding that choice really is.
What this means for you
- Don't spend time trying to calculate your CAO points as a US applicant -- that system is built for the Leaving Cert, and most US applicants are evaluated through a completely separate direct-entry process instead.
- Go straight to your target university's own international-admissions page, not a general CAO guide -- Trinity's process and requirements aren't necessarily UCD's or Galway's.
- Have your SAT or ACT score ready, but check whether your target school requires it outright or considers it as one part of a broader file -- Trinity, for one, currently allows GPA/transcript-based evidence in place of a test score.
- Treat the course you apply to as a real, binding choice from day one, the same as a UK application -- there's no CAO-style points cushion to fall back on if you're unsure.