A US application typically asks for two or three individual teacher recommendation letters plus a separate school counselor letter -- four documents, from four different people, each writing independently. UCAS asks for exactly one reference, submitted once, capped at 4,000 characters. That structural difference changes both who you should ask and what you should expect them to actually cover.
One combined reference, not several independent letters
UCAS requires a single reference per application -- not one per recommender the way the Common App does. In practice, that reference is often built collaboratively: a subject teacher may contribute input on your academic work specifically, which then gets consolidated and finalized by a Head of Sixth Form, school counselor, or Head of Department before submission. For a US applicant, this most often means your school counselor is the one actually submitting the reference through UCAS, whether or not they personally wrote every word of it -- the same role a UK sixth-form or college tutor plays for a UK student.
Who's eligible to write it
UCAS requires the reference to come from someone who knows you academically or professionally -- a teacher, tutor, employer, or supervisor. It explicitly cannot come from a family member, friend, partner, or ex-partner, regardless of how well they know your work. If you're an independent applicant with a genuine gap between finishing school and applying -- not the typical case for most US high schoolers, but relevant if it applies to you -- UCAS's guidance for independent applicants covers who can substitute for a school-based referee.
What the reference actually has to cover
Unlike a US recommendation letter, which often leans on anecdote and personal impression, UCAS references are expected to be specific and evidence-based: your genuine interest in your chosen subject, your academic performance and potential, and your capacity for the independent work university study requires -- all supported by concrete detail, not general praise. Guidance used by UK universities for reference-writers typically breaks this into distinct sections: context about your school (especially useful for an international applicant, since a US high school's grading and course structure isn't something a UK admissions reader necessarily already knows), any mitigating circumstances affecting your record, and a substantive academic assessment that's expected to take up the majority of the available space.
The reference can carry your predicted grades
This is the piece most likely to catch a US applicant off guard: your reference is also the vehicle through which predicted grades get submitted, for whatever part of your record genuinely isn't finished yet. As our piece on predicted grades covers, if you already have a completed SAT or ACT score, that's a real result, not a prediction -- but any tests still scheduled for senior year, or final coursework grades not yet in, are exactly what the predicted-grade mechanism exists to estimate. Your counselor is the one entering that information, which is another reason to talk to them early, not right before your UCAS deadline.
Why this means talking to your counselor earlier than you might for a Common App letter
Because the process consolidates multiple inputs into one final document, and because that document may need to explain your school's specific context to an unfamiliar international reader, giving your counselor real lead time matters more here than it might for an individual US teacher letter. A US applicant should expect to walk their counselor through exactly what UCAS needs -- the character limits, the expectation of specific evidence over general praise, and the fact that predicted grades or outstanding test dates need to be stated explicitly -- since a counselor unfamiliar with UCAS may not know its format differs this much from a typical US recommendation letter.
What this means for you
- You need one strong combined reference, not several separate letters -- talk to whoever is coordinating it (usually your school counselor) early, since it's a more involved document than a single US teacher letter.
- The reference must come from someone who knows you academically or professionally -- family members and friends are explicitly disqualified, regardless of how well they know you.
- Make sure your predicted grades and any outstanding test dates are stated clearly -- this is the vehicle for exactly that information, and it needs to be explicit, not implied.
- Give your counselor real context about UCAS's expectations -- specific, evidence-based claims over general praise, and an explanation of your school's context if they're not already familiar with UCAS references.