International Mathematical Olympiad vs Regeneron ISEF 2026

Comparing two elite STEM opportunities. International Mathematical Olympiad is a olympiad while Regeneron ISEF 2026 is a competition.

International Mathematical Olympiad Regeneron ISEF 2026
Prestige Tier Tier 1 — Elite Tier 1 — Elite
Type Olympiad Competition
Organization IMO Official Regeneron
Acceptance Rate Extremely competitive; approximately 0.01-0.1% of high school students worldwide reach IMO. For USA: ~6 students selected from 300,000+ AMC participants annually Roughly 1,700 finalists are selected from 365 affiliated fairs worldwide. Getting to ISEF requires first winning regionally, which itself is competitive. Estimated <1% of all science fair participants globally reach ISEF. At the ISEF itself, approximately 600 of the 1,700 finalists (~35%) receive some award.
Applicants Approximately 5,000-6,000 contestants from 100+ countries compete at IMO annually. USA sends 6 representatives from ~300,000 AMC 10/12 participants Millions of students compete in science fairs globally each year; approximately 1,700–1,800 reach ISEF as finalists
Deadline
Cost to Apply Free Free
US Only No / International No / International
Grades High school students only; typically grades 9-12 (ages 13-19) Grades 9–12 (high school students only; middle schoolers compete in the separate Junior Innovators Challenge)
College Impact Extremely positive and highly prestigious. IMO medalists (especially gold) are exceptionally rare and highly valued by top universities globally. Impact includes: (1) Gold/Silver medalists essentially... ISEF finalist status is one of the most powerful extracurricular credentials in college admissions. Being named an ISEF finalist (simply qualifying) is Tier 1 on most admissions frameworks. Grand Awar...