The Toughest Exams in the World (and How to Prepare for Them)

Some exams test more than knowledge — they test how well you can prepare under pressure, sustain months (or years) of study, and perform when the margin for error is razor-thin. A handful of exams show up again and again on "world's hardest" lists — not because any one of them is objectively worse than the others, but because each combines a huge, self-selected applicant pool with a tiny number of seats or passes on offer. Here's a close look at the exams that consistently earn that reputation, what they actually test, roughly how selective they are, and how people who pass them tend to prepare.

A quick note on the numbers below: pass rates, acceptance rates, and applicant counts move every year and are reported inconsistently across outlets, so treat every figure here as "reported" or "roughly" rather than fixed — always check the official exam body for the current cycle before you plan around a specific number.

Gaokao (China's National College Entrance Examination)

China's Gaokao is sat by more than 12–13 million students each year, making it arguably the single largest standardized exam on Earth by volume (Study International; Birchwood University). It runs over two intense days and covers Chinese literature, mathematics, a foreign language, and further subjects depending on whether a student is on the science or humanities track.

What makes the Gaokao brutal isn't just the syllabus — it's the scale of the sorting. In Guangdong province, China's most populous, only around 3% of candidates scored above 600 out of 750 in 2022, the rough threshold for a seat at a top-tier university, and roughly 17% of students nationwide retook the exam that year after an unsatisfactory result (The Straits Times, via Study International). China's most selective universities admitted an average acceptance rate of about 6.7% in 2021 (roughly 670,000 of 10.78 million applicants) — for comparison, Oxford's undergraduate acceptance rate was around 14% the following year (British Council, via Study International).

Preparation for the Gaokao often starts years in advance, with study days commonly running well beyond a normal school schedule. Cities have been known to reroute traffic and quiet construction near exam halls on test days — a sign of how much social weight the exam carries.

IIT JEE (Indian Institutes of Technology Joint Entrance Examination)

The Joint Entrance Examination, commonly called IIT JEE, is the gateway to undergraduate engineering seats at India's Indian Institutes of Technology and other top engineering schools. It runs in two stages: JEE Main, which is open to a broad pool of applicants, and JEE Advanced, which only those who clear Main may sit — and which alone determines admission to the IITs. Questions are objective-format but multi-concept, designed to test applied reasoning under time pressure across physics, chemistry, and mathematics rather than rote recall.

The scale of competition is the defining feature. Reported figures put JEE Main applicants at roughly 1.4–1.5 million a year, of whom only a few hundred thousand qualify to attempt JEE Advanced (Birchwood University). Of that already-filtered group, pass rates for JEE Advanced itself have been reported in the roughly 20–30% range in recent years — for example, about 48,248 of over 180,000 JEE Advanced candidates passed in 2024, close to 27% (The Hindu, via Study International) — but the number that actually matters most to applicants is the tiny fraction who go on to secure a seat at one of the most sought-after IITs, commonly cited as under 1% of the original applicant pool.

UPSC Civil Services Examination

India's Union Public Service Commission (UPSC) Civil Services Examination selects officers for the Indian Administrative Service (IAS), Indian Police Service (IPS), Indian Foreign Service (IFS), and other central government services. It runs across three stages — a Preliminary Examination, a Main Examination, and a Personality Test (interview) — covering general studies, an aptitude paper, and an optional subject the candidate chooses in advance.

Reported figures put roughly 1.3 million aspirants sitting the Preliminary exam each cycle, of whom fewer than 15,000 typically qualify for the Mains, before a much smaller number make it through the interview stage to a final appointment — overall selection rates are commonly cited as somewhere between 0.2% and 0.4% (Birchwood University). Much of the exam's difficulty comes from the sheer breadth of the syllabus — history, polity, economics, science and technology, international relations, ethics, and a self-chosen optional subject — combined with a preparation cycle that commonly runs one to three years and, for many candidates, multiple attempts.

Suneung (South Korea's College Scholastic Ability Test)

South Korea's Suneung, formally the College Scholastic Ability Test (CSAT), is a single nine-hour exam held on one day each November that plays an outsized role in determining a student's university, and by extension their career track and social standing. The exam carries enough national weight that authorities have reportedly delayed stock market and bank opening times, briefly restricted flights near test centers during listening sections, and dispatched police escorts to help latecomers reach exam halls on time (Birchwood University).

Around 80% of Suneung test-takers do go on to some form of higher education, since South Korea has a very high tertiary enrollment rate overall — the real difficulty is concentrated at the top, where admission to the most prestigious universities is extremely competitive and even small differences in score can be decisive. English has been cited as one of the toughest sections in recent years, with roughly 3% of candidates achieving the top grade band.

USMLE (United States Medical Licensing Examination)

The USMLE is the three-step exam that anyone practicing medicine in the United States — including international medical graduates — must pass, jointly administered by the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). Step 1 covers foundational biomedical science, Step 2 CK tests clinical knowledge and patient management, and Step 3 assesses independent clinical decision-making; all are heavily scenario- and case-based rather than fact-recall, which is part of why they're demanding even for well-prepared candidates (Birchwood University).

Preparation timelines are long by design — candidates commonly report 6 to 18 months of dedicated study for Step 1 alone — and because each step builds toward a residency application, the stakes compound: a weak Step 1 or Step 2 CK score can narrow which residency programs are realistically in reach later on. Exact current pass rates are best confirmed directly with the NBME/USMLE program, since they vary by step, year, and candidate group (US MD graduates historically pass at much higher rates than first-time international medical graduates).

California Bar Exam

The California Bar Exam qualifies candidates to practice law in California and is widely cited as one of the toughest state bar exams in the US. It's a two-day test combining five one-hour essay questions, a 90-minute Performance Test that simulates real attorney work (sorting relevant facts from a case file and producing a work product), and 200 multiple-choice questions on the Multistate Bar Examination (MBE) — 1,390 total points are available.

California's bar has historically posted one of the lower pass rates among US state bars, reported as low as around 18% in some sittings, partly because such a large and varied pool of candidates sits it, including graduates of schools not accredited by the American Bar Association (Birchwood University). Pass rates fluctuate meaningfully by administration and candidate pool, so always check the State Bar of California's own released statistics for the most recent cycle rather than relying on a single historical figure.

CFA Exam (Chartered Financial Analyst)

The CFA Program is a three-level professional qualification for careers in investment management and financial analysis, covering ethics, economics, financial reporting and analysis, corporate finance, and portfolio management. Level 1 tests foundational tools across ten topic areas; Level 2 shifts to asset valuation and applying those tools in context; Level 3 focuses on portfolio management and wealth planning, and requires candidates to synthesize the entire curriculum (Birchwood University; Investopedia).

Pass rates are published each cycle by the CFA Institute and move year to year — first-attempt Level 1 pass rates have been reported around the mid-30s percent in recent cycles (for instance, about 35% in early 2024, per Bloomberg), and 10-year averages compiled by exam-prep site 300Hours put roughly 39% for Level 1, 45% for Level 2, and 50% for Level 3 (300Hours). What makes the CFA a multi-year undertaking rather than a single hard day is that all three levels must be passed in sequence, and most candidates need several years — plus several hundred hours of study per level — to finish the full program. CFA Institute research has also linked passing Level III to meaningfully higher reported compensation, which is part of why so many finance professionals attempt it despite the odds.

GRE and other graduate-admissions tests

The Graduate Record Examination (GRE), run by the Educational Testing Service (ETS), is accepted by graduate programs in the US and beyond and tests verbal reasoning, quantitative reasoning, and analytical writing. It's taken by several hundred thousand candidates annually, and while it isn't "pass/fail" in the way a bar exam is, the effective bar for admission to elite programs is extremely high — top MBA and graduate programs have reported incoming-class average scores well above the exam's midpoint, with some leading business schools citing class averages in the 325–330 range out of 340 (Study International, citing Poets & Quants). The difficulty here is less about a fixed pass rate and more about the fact that admission is a relative, not absolute, bar — you're competing against an applicant pool that skews very strong.

Mensa admission test

Unlike the exams above, Mensa's qualifying test isn't tied to a career or degree — it's a pure IQ threshold, open to anyone regardless of age, background, or education. Candidates must score in the top 2% of the general population on an approved, standardized IQ test to qualify for membership, and Mensa has no upper or lower age limit — its membership has reportedly included children as young as two and adults past 100. It's included on most "hardest exams" roundups not because of a low pass rate in absolute numbers, but because a genuine top-2% cognitive threshold is, by definition, out of reach for the other 98% of any given population, regardless of how much they study.

How these exams compare

How to prepare for a tough exam

Whatever exam you're facing, a few habits consistently separate candidates who pass from those who don't:

• Start early. Build a study plan with a realistic daily or weekly routine rather than cramming close to the date. Multi-stage exams like UPSC or the CFA Program reward preparation measured in months or years, not weeks.
• Know the syllabus and format cold. Understanding exactly what's tested — and how — lets you focus your effort on what matters most, rather than over-studying topics that carry little weight.
• Practice under real exam conditions. Timed mock tests build both speed and the composure you'll need on the day, especially for exams like the Gaokao, Suneung, or JEE Advanced where time pressure is part of the difficulty.
• Get help when you're stuck. Teachers, mentors, and study groups can clarify concepts faster than studying alone, and can help you spot blind spots you wouldn't catch on your own.
• Protect your motivation. Long preparation cycles are as much about consistency as raw ability — plan for rest, not just revision, particularly for exams that take a year or more to prepare for.
• Verify the current format and passing bar yourself. Exam structures, fees, and pass thresholds change between cycles — always check the official exam body's site before you commit a study plan to a specific number.

FAQ

Which is the hardest exam in the world? There's no single agreed-upon answer — it depends on whether you're measuring by acceptance rate, syllabus breadth, or sheer number of competing candidates. China's Gaokao and India's UPSC Civil Services Examination are among the most frequently cited, largely because of the scale of competition (millions of candidates for a small number of top-tier outcomes), but exams like IIT JEE Advanced, the California Bar, and the CFA Program are consistently named alongside them for different reasons.

Do these exams have a fixed pass rate? No. Pass rates, acceptance rates, and applicant numbers for every exam on this list change from year to year and are reported differently across sources. Treat any specific percentage as a rough historical snapshot and confirm the current figure with the exam's official administering body before you plan around it.

Are academic entrance exams and professional exams (like the CFA or bar exam) really comparable? Not directly — they gate very different things (a university seat versus a professional license) and are scored differently. They're grouped together here because each combines a demanding syllabus with intense competition or a high absolute bar, which is the common thread in most "hardest exams" discussions.

Do I need to take one of these exams to study abroad? No. Most of these are country- or profession-specific gateway exams. If you're planning to study abroad generally, the more relevant tests are usually language-proficiency exams (like IELTS or TOEFL) or standardized admissions tests specific to your target country and program — check with your target universities directly for what they actually require.

How long should I prepare for a high-stakes exam like these? It varies enormously by exam — from several months of full-time study (JEE, Gaokao, USMLE Step 1) to a multi-year commitment across sequential levels (CFA, UPSC with retakes). The safest approach is to look up the official recommended or typical preparation timeline for your specific exam rather than assuming one size fits all.

Sources

• Study International — "20 of the world's toughest exams"
• Birchwood University — "Top 10 Toughest Competitive Exams in the World"
• The Straits Times — Gaokao coverage, via Study International
• British Council — Gaokao admission-rate reporting, via Study International
• The Hindu — JEE Advanced 2024 results, via Study International
• Bloomberg — CFA Level I pass rate reporting
• 300Hours — CFA pass rates, 10-year averages

If one of your goals is studying abroad, choosing the right program matters as much as passing any entrance exam. You can compare options directly on TheUniFinder's university listings, browse programs by field, check the scholarships directory, or use the scholarship finder to see what funding might be available once you've cleared the exam stage.