USA Junior / USA Mathematical OlympiadUSAJMO / USAMO

The format is identical: two consecutive days, three proof problems each day, 4.5 hours per day, six problems scored out of 42. The difference is the field and the difficulty. USAJMO is for students in grade 10 or below who qualified through the AMC 10 track and uses somewhat easier problems; USAMO is for those who came through the AMC 12 track. Placement follows your qualification path — it is not a choice. USAJMO is not a lesser award.

No longer. The MAA has announced that 2027 USAMO and USAJMO qualification is based primarily on AIME performance, with AMC scores no longer a selection factor. In effect the AMC's role shrinks to earning the AIME invitation, and those 15 AIME questions decide whether a student reaches the olympiad. Roughly 250-300 students are invited to each, with thresholds published by the MAA after results.

This is where outdated information trips families up most. The index used to be the AMC score plus 10 times the AIME score, was revised for 2025-26 to the AMC score plus 20 times the AIME score, and for 2027 the MAA has announced that AMC scores no longer count at all, with selection based primarily on AIME. So the index calculators and 'what index do I need' threads circulating online are largely obsolete. Go by the MAA's announcement for the current year.

USAMO and USAJMO are for students in the United States and Canada, and the official rules place explicit conditions on a participant's citizenship or residency; international students in the U.S. on a student visa are generally outside the invited pool. The wording can be adjusted year to year, which matters most for recent immigrants and families who have just moved into a U.S. high school. Confirm the current eligibility clause on the MAA site before the AMC.

It is written simultaneously at designated sites across the U.S. and Canada; invited students are assigned a site by the MAA rather than choosing one. The contest runs over two days, 10:00 a.m. to 2:30 p.m. Pacific each day (1:00 to 5:30 p.m. Eastern), three problems per day. Full rigorous proofs are required — an answer alone earns nothing — and no calculators or reference materials are permitted. For the 2027 dates, rely on the MAA's notice to invited students.

USAMO awards gold to roughly the top 6%, silver to about the top 12%, and bronze to about the top 18%; USAJMO names Winners and recognizes roughly the top 20%. In both, scoring 14 or more out of 42 earns Honorable Mention. The real ceiling is an invitation to MOP, the summer olympiad program from which the U.S. IMO team is chosen — only a few dozen students a year, and an internationally recognized marker.

Honestly, four to six years of sustained work from the AMC 8 stage: build fundamentals on AMC 8, clear the AIME cutoff reliably on AMC 10/12, get AIME consistently to 8 or above, then spend another year or two specifically on writing proofs. The last step is the one families underestimate — going from solving a problem to writing an argument that survives 0-7 grading is a different skill. It does not reward cramming and suits planning from late elementary or middle school.

It is the heaviest credential on the American high school math ladder. With roughly 250-300 invitees each per year, it is a top-fraction-of-a-percent marker that admissions officers at elite STEM programs recognize by name, and it carries genuine weight in the Common App Honors section or under Activities & Awards on the University of California (UC) application. But it is the natural outcome of years of training, not an admissions tactic — chasing USAMO for the sake of an application is essentially not a workable plan.