The hardest majors in the US: A full ranking by three objective measures

Ask which US college major is hardest and the honest answer starts with a question back: hardest by what measure? Completion rate? Early attrition (the students who start in a major and switch out)? Weekly study hours? Grade distribution? Each measure produces a different ranking, and combining them into a single hardest list smooths over the differences that really matter when you're picking a major.

This piece treats them separately and grounds each in a primary source: NCES (the National Center for Education Statistics) for completion and attrition, and NSSE (the National Survey of Student Engagement, run by Indiana University Bloomington) for study hours. We ground the main figures in primary sources where they exist and flag where the data are thinner. This is the US companion to our hardest degrees in the UK piece, but the US system measures difficulty differently, so the comparison isn't direct.

Four measures come up repeatedly in the US data. Completion rate is the share of students who finish a bachelor's within six years of first enrolling. Early attrition is the share of students who declare a specific major (usually STEM in NCES's flagship 2014 report) and switch out or leave higher education within a couple of years. Study hours per week captures the workload demand outside class time. GPA distribution reflects how grading works within a major.

Each measure surfaces a different dimension of difficulty. Completion rate combines academic difficulty with institution effects, financial pressure, and career reasons. Early attrition isolates the students who tried a major and left it, which is a more direct signal about the major itself. Study hours capture workload demand, while GPA reflects grading culture as much as content difficulty (some departments run harder curves than others). No single measure captures hardest cleanly, so ranking majors sensibly means holding all four in mind.

NCES's Condition of Education publishes the definitive US figures on undergraduate degrees and graduation rates. For 2021-22, US colleges conferred approximately 2.0 million bachelor's degrees, with the six most-conferred fields making up 58% of the total:

The overall 6-year graduation rate at 4-year US institutions is 64% for the fall 2014 cohort (NCES Condition of Education, the latest available at time of writing). The rate varies substantially by institution type: 63% at public 4-year institutions, 68% at private nonprofits, and 29% at private for-profits. It also varies sharply by selectivity: 90% at institutions accepting fewer than 25% of applicants, 28% at open-admissions institutions.

What NCES data doesn't publish cleanly is a 6-year graduation rate broken by the entering major (the field a student declared as a freshman). NCES does publish graduation numbers by field of graduation (which counts students by what they graduated in, not what they started in), so major-specific completion figures need to be read with that caveat.

The most-cited US data on major switching is NCES's 2014 STEM Attrition report. It found that among students who entered a bachelor's program declaring a STEM major, around 48% had switched to a non-STEM major or left higher education entirely within a few years. That figure comes from students who started in 2003-04. The same report found attrition was as high or higher in several non-STEM fields (56-62% in humanities, education and health sciences). A later NCES study of 2011-12 starters found STEM students changed major slightly more often than non-STEM students (35% against 29%).

Early attrition doesn't equal degree failure. Many STEM-to-non-STEM switchers go on to complete bachelor's degrees in their new majors, and students who stay in STEM through the first two years usually go on to complete. What early attrition signals is where students most often change course during the first two years; in STEM that filtering tends to happen in the math and physics sequences.

Engineering has the reputation for being the hardest US major, and NCES data shows its early attrition is substantial (about 40%), though computer and information sciences is higher (59%). Reasons that show up repeatedly in follow-up studies include the rigor of the first-year math sequence (Calculus 1, 2, and 3 in sequence, plus Physics 1 and 2), the pace of the introductory engineering courses, and curve grading that keeps averages low even for capable students.

Homework loads are heavy (weekly problem sets across multiple courses). Women earned roughly 23% of US engineering bachelor's degrees in 2021 (NCES Digest of Education Statistics, table 325.45), which is a demographic detail worth noting for prospective students who care about program culture.

If you're heading into engineering, a strong AP schedule builds the math and science foundation. AP Calculus (AB or BC, with BC preferred if it's available) plus AP Physics is the standard preparation.

Physics and Chemistry sit alongside Engineering in the high-early-attrition camp. NCES's STEM Attrition report grouped them together with Math and Computer Science under STEM; the physical sciences aggregate has similar first-two-year attrition patterns to Engineering.

What drives it: the leap from high school physics or chemistry to university-level treatment is steep. Physics degrees pile on mathematical formalism (differential equations, linear algebra, complex analysis) that students may not have prior grounding in. Chemistry degrees demand fluency across quantum mechanics, thermodynamics, kinetics, and synthetic organic chemistry, often taught simultaneously. Students who did well at AP or high school level can find the university leap harder than the content itself suggested.

Biological and Biomedical Sciences (7% of all 2021-22 US bachelor's degrees, about 131,500) has moderate early attrition and high completion once students commit. What makes it hard, particularly for pre-med students, is competition rather than raw content difficulty.

Organic chemistry (typically a two-semester sequence in sophomore year) has a reputation as the pre-med filter. It isn't the hardest chemistry course objectively; it's just where pre-med competition concentrates, and many students find the grading there especially competitive. Students who don't survive orgo often re-route into biology-adjacent majors or completely different fields.

Strong prep for a life sciences major usually includes AP Biology and AP Chemistry, plus at least Calculus AB. AP scores can also earn credit for introductory courses at many colleges, which is worth checking on the College Board's AP Credit Policy Search before you enroll.

Computer Science had the highest attrition of any STEM field (59%) in NCES's STEM attrition study. It has also grown rapidly as a declared major. The first-year filter is usually a data structures and algorithms course that many students find harder than they expected, combined with a discrete mathematics requirement that isn't obvious from the outside.

Many students enter CS with limited prior programming exposure and find that the pace of the introductory sequence exceeds what they can manage while also taking a full course load. Others enter CS for career reasons and discover that the theoretical parts of the major (formal reasoning, mathematical proof, algorithm analysis) aren't what they expected the field to be about.

AP Computer Science A is useful preparation because it introduces the programming discipline and object-oriented thinking that college CS assumes.

Business at 19% is the most-conferred US bachelor's degree. Completion rates are moderate and study loads are moderate. It's less academically demanding than the STEM majors above by most measures, but it isn't a soft major; the difficulty comes from breadth (accounting, finance, statistics, management, marketing, operations, all in the same degree) rather than from depth in any one area.

What can trip up business students is quantitative coursework that isn't obvious from the outside. Introductory statistics, financial accounting, and managerial economics are more mathematical than the major's reputation suggests, and students who chose business to avoid math can struggle with them. Preparation with AP Macroeconomics and Microeconomics, plus AP Statistics and Calculus AB, gives a smoother start.

Health Professions at 13% is the second-most-conferred US bachelor's field. What makes it hard is the combination of demanding clinical coursework, licensure gates (state boards, NCLEX for nursing), and clinical rotation demands that make the schedule inflexible.

Completion rates for nursing programs specifically are relatively high once students are enrolled (nursing is selective at entry and highly structured throughout), but attrition during prerequisite courses (anatomy, physiology, microbiology) before clinical rotation can be substantial. Students who want a nursing career often complete the prerequisites at one institution and transfer into a nursing program at another, which shows up as institutional switching rather than dropping out entirely.

English, History, Philosophy, Foreign Languages, and other humanities majors have moderate completion rates and moderate weekly contact hours. What makes them hard is the volume of reading and the demands of essay-based assessment. Humanities students report heavy reading and writing loads, largely spent on primary sources and drafting essays, though NSSE data show engineering students report the most weekly preparation time overall (around 19 hours a week).

The demand isn't uniform across the humanities. Philosophy majors post some of the highest average GRE verbal and analytical writing scores of any intended major (ETS Guide to the Use of Scores data), which is a proxy signal about the analytical rigor the discipline demands.

The number of humanities degrees conferred has been falling nationally over the past decade as students shift toward business and STEM. Students who stay in humanities and finish typically report high engagement in NSSE surveys, but overall enrollment (and by extension the number of completions) is dropping.

The 6-year graduation rate at 4-year US institutions is 64% overall, but that hides a huge institution-selectivity gap. NCES data shows the rate rising to around 90% at institutions that accept fewer than 25% of applicants and falling to around 28% at open-admissions institutions.

Within a given major, that spread is even larger. Engineering completion at MIT is very different from engineering completion at a large state university with open admissions in engineering. When you see any single US major difficulty number quoted, ask which institution or set of institutions it came from; a national average smooths over a spread of 3x or more between the most and least selective schools.

A few practical takeaways. Fit and preparation matter more than the abstract hardest label. A student well-prepared for engineering (with strong AP Calculus and AP Physics scores) will find engineering hard but manageable; a student without that preparation will find it much harder. The single most useful lever incoming freshmen have is honest self-assessment about their preparation for the major's demands.

Look at your AP scores as a preview: a 4 or 5 in the relevant subject is a strong signal, and the College Board's AP Credit Policy Search shows how each institution treats each AP subject. A 5 in Calculus BC can save you two semesters of introductory calculus at many colleges. That either shortens your degree or opens up electives, both of which help with load management in a demanding major.

Check your target institutions' Common Data Set files. Section B of the CDS reports institutional graduation and retention rates. It won't break down by major, but it gives you a starting benchmark. For finer-grained major-level graduation figures, tools like the CDS Explorer at collegetransitions.com aggregate CDS data across institutions.

And don't let a hardest major label push you into or away from a field you genuinely want. The published data show that fit, preparation, and institution match matter more than the raw difficulty ranking. If you're weighing AP options, our best AP combinations for college admissions piece walks through how to build a coherent stack aligned to your intended major.