How to Apply to Physics at Caltech: Admitted to the Institute First, a Common First-Year Core, Then Choosing the Physics, Applied Physics or Astrophysics Option at the End of the First Year, with Requirements for Domestic, International (Including Chinese) and Transfer Students

The California Institute of Technology (Caltech) calls majors “options”. Physics sits in the Division of Physics, Mathematics and Astronomy. Caltech has six academic divisions, and every undergraduate takes a core curriculum that spans them. Below is what Caltech’s websites say, for domestic students, international students (with a separate section for applicants from China) and transfer students. Mathematics, chemistry, engineering, computer science and other majors are not covered here.

1. Physics and related options

• Physics option (Ph): listed on both the admissions site and in the catalog. The catalog says it offers instruction in the fundamentals of modern physics and a foundation for graduate study, which is generally necessary for a career in basic research, and that it also forms a basis for work in a variety of applied fields. The physics department’s page says physics majors often become leading researchers in universities and industry.
• Related options: the admissions site’s list of majors also includes Applied Physics (APh), Astrophysics (Ay), Environmental Science and Engineering (Physics), and the Interdisciplinary Studies Program, in which a student designs their own requirements under faculty supervision. The catalog says the Applied Physics option extends the principles of pure physics to the development of new technologies, with research focused on problems of technological importance, and that astrophysics uses the apparatus and methodology of physics to understand the universe. The pages read do not list separate biophysics, chemical physics or physics education options, or a joint physics-mathematics option; not published.
• Double majors: the physics department says you can double major and should plan with your advisor so you can still graduate on time. The catalog says students petitioning to double-major in Astrophysics and Physics must present a plan with at least 92 units counted solely toward the Ay requirements and at least 92 units counted solely toward the Ph requirements.
• 3-2 engineering dual degree: no 3-2 program between physics and engineering at Caltech appears in the pages read. The catalog’s “3/2 Dual Degree Plan” is a different thing: a transfer program for students from a select group of liberal arts colleges (see section 9).
• After graduation: the pages read do not print graduate destinations or employment data for physics; not published.

2. Requirements of the physics option (catalog)

• Required courses: the catalog lists a laboratory course Ph 3 (other labs such as Ph 5 or Ph 8 bc may be substituted), Ma 2 and Ma 3, Ph 12 abc (waves, quantum physics and statistical mechanics, the intensive version of the sophomore physics course for those planning further study in physics), Ph 6 and Ph 7 (physics laboratory), Ph 70 (oral and written communication), Ph 106 abc (topics in classical physics), Ph 125 ab (quantum mechanics), and a computational physics course such as Ph 21 or Ph 22. The first five requirements should be completed by the end of the second year; Ph 6 and Ph 7 are each offered only once a year and cannot be taken pass/fail.
• Laboratory and thesis: the catalog requires 18 units of Ph 77 (advanced physics laboratory), or 27 units of Ph 78 (an experimental thesis project), or Ph 77 combined with APh 77, Ay 105 or Ph 177. The physics department says you can do a senior thesis (Ph 78/79) and/or take a research course (Ph 172); both let you do research during the school year and earn credit toward the degree.
• Electives: 90 units of advanced physics electives, plus 9 units of science and engineering electives outside Ph, Ay, APh, Ma and ACM. Passing grades must be earned in a total of 486 units.
• Grade condition for staying in the option: the catalog says students must maintain a grade point average of 1.9 or better each year in the subjects listed under the division to remain in the physics option.
• Specializing: the physics department says you can specialize unofficially by tailoring advanced electives, for example toward astrophysics, high-energy physics or quantum information, and can talk with your advisor; no separate degrees are listed for these.
• Applied Physics option (APh): the catalog requires APh/EE/MS 9, APh/EE 23 and APh/EE 24 (with one of them replaceable by Ph 3, 5, 6, 7 or Ch 6 with the option representative’s permission), Ph 12 abc, Ph 106 abc, Ph 125 ab, Ma 2, Ma 3, a senior thesis (APh 78 or 79) or three terms of listed courses (such as EE/APh 123 or Ph 77 ab, with substitutions needing prior approval), and four advanced applied physics courses. The total is also 486 units, no option requirement may be taken pass/fail, and a GPA below 1.9 at the end of the year may lead to refusal to continue in the option.
• Astrophysics option (Ay): the catalog requires astronomy courses such as Ay 20, 21, 101 and 102, plus Ma 2, Ma 3, Ph 12 abc (or Ph 2 abc), Ph 125 ab and Ph 106, three laboratory courses, 63 more units of Ay or Ph courses and 27 units of science or engineering electives outside the Division; the total is 486 units.

3. How admission works: the Institute first, an option at the end of the first year

• You do not choose an option when applying: the physics department’s FAQ says, “All undergraduate admissions are handled centrally through the admissions office. The option does not admit students directly.” The application requirements page read has no item for choosing a major.
• A common first year: the admissions site says every first-year student takes the same classes in their first two terms and does not declare a major until the end of the first year. The physics department says students declare an option toward the end of the freshman year, after which physics students have a lot of freedom to customize the degree.
• Staying in, and moving into, physics: the catalog’s grade condition is above (a 1.9 GPA each year). Whether the physics option has an enrollment cap, and the conditions for moving into it from another option, are not published in the pages read; ask the physics department’s undergraduate option representative.
• Physics competitions: the application pages read do not say how competitions such as USAPhO are viewed; not published. The admissions site has a “Demonstrating STEM Preparedness” page that was not read for this article.
• Research: the admissions site says nine out of ten students do research while at Caltech. The physics department says the Summer Undergraduate Research Fellowships (SURF) are the most popular option, in which students conduct paid research over the summer with a member of the physics department, and that the vast majority complete at least one. Occasionally faculty have funding for paid positions during the school year or summer, at the faculty member’s discretion.

4. Preparation

• High school courses (the admissions site and the catalog agree): four years of math including one year of calculus, one year of physics, one year of chemistry, one year of biology (recommended), four years of English, and two years of history and/or social sciences (three or more recommended). Students who run out of high school math before senior year need not have four years.
• If your school does not offer a course: when calculus, chemistry or physics was unavailable or there was an unresolvable course conflict, and both student and counselor document the issue, Caltech accepts exam scores or a Schoolhouse.world course challenge instead: a 5 on AP Calculus AB or BC, AP Chemistry, AP Physics 1, 2 or C; a 6 or 7 on IB Mathematics HL, Chemistry SL/HL or Physics SL/HL (the catalog says IB Mathematics SL does not meet the requirement); or a Schoolhouse.world challenge in AP/College Calculus BC, AP/College Chemistry or AP/College Physics 1. AP and IB exams must be taken by the application deadline, and the certificate is due within a week after it. The academic requirements page says these are the only avenues “for incoming fall 2026 first-year applicants”, with no exceptions; check whether the same applies to fall 2027.
• You may take them for the first time in senior year: the website says many students do, but Caltech must be able to see semester or in-progress grades by the application deadline.
• Physics core after you enroll: the catalog says every student takes first-year physics Ph 1 abc (27 units) and first-year mathematics Ma 1 abc, or the Integrated Core alternative. Over the summer all new students take a Foundations Assessment covering high school chemistry, physics and mathematics, which also determines Ma 1a and Ch 1a section placement.
• Placement and advanced placement tests: the admissions site says you must either take Ph 1 abc or place out through the advanced placement exam given over the summer by the Division of Physics, Mathematics and Astronomy. The physics department says the Ph 1a advanced placement test is completely voluntary and that the summer before freshman year is the only chance to take it; exceptional results may allow the Ph 1b exam, taken in person after you start, and then the Ph 1c exam.
• AP/IB and college credit: the physics department says that for an AP course or a course at a local college, “We do not accept any credits from other institutions”; credit comes only through those placement exams. The catalog says college credit for AP or IB classes is not automatic and is sometimes granted by department faculty, awarded at registration each fall. The two statements are not identical. The pages read do not give a table converting AP Physics 1/2/C or IB Physics scores to credit; not published, so ask the physics department.
• Honors sequences: the catalog describes Ph 12 abc as an intensive version of the sophomore physics course for those planning further study in physics. Other honors entry points are not published in the pages read.

5. Dates and materials (fall 2027)

• Two rounds: Restrictive Early Action (REA, non-binding) closes November 1, 2026; all required and supplemental materials are due by November 6, standardized testing must be completed before November 30, decisions (admit, defer, deny) come in mid-December, and the reply deadline is May 1, 2027. Regular Decision (RD) closes January 4, 2027, materials are due by January 10, testing must be completed before December 31, 2026, decisions come in mid-March, and the reply deadline is May 1. One RD paragraph prints the reply date as “May 1, 2026”, while the rest of the same page says May 1, 2027, which should be the right one. REA applicants may not apply Early Action or Early Decision elsewhere, with listed exceptions (institutions outside the US, public universities with non-binding policies and so on).
• Materials: Common App or QuestBridge application, a USD 85 fee (or fee waiver), two teacher letters (one STEM: calculus or beyond, chemistry, physics or biology; one humanities or social science: English, history, government or economics), a School Report from the counselor (who may add a letter), official secondary transcripts for grades 9 to 11, a Mid-Year Report, SAT or ACT scores, and all AP and IB exams taken, whatever the score; there are also essays (the catalog says the supplemental essays are updated each August 1 on the admissions site). International applicants add English proficiency scores. Optional supplements include a research paper or portfolio.
• Testing: Caltech requires the SAT or ACT and does not require the ACT writing or science subscores; it does not consider the ACT composite but each subscore. Scores are shown in “buckets”: SAT Math or Reading & Writing 780 to 800 (ACT 35 to 36) is Bucket A, 750 to 770 (ACT 33 to 34) is Bucket B, and the committee sees only the bucket; below 750 (ACT below 33) is Bucket C and the exact score is shown. There is no minimum score, and Caltech superscores. The page says successful applicants have traditionally had 700 or higher on each SAT section or 30 or higher on each ACT section, with no minimum and no expectation of a perfect score. Students who could not sit a test can explain in the application.

6. Domestic students

• Cost (2026-27, undergraduate, on campus): tuition USD 68,574, fees USD 2,655, housing USD 12,711 and food USD 9,285, for direct costs of USD 93,225; indirect costs (books, course materials, supplies and equipment USD 1,428, personal expenses USD 3,969) total USD 5,397. Fees do not include the Student Health Insurance Plan (USD 5,388, optional if you have comparable coverage), and entering students pay a one-time USD 600 orientation fee. The pages read do not distinguish in-state from out-of-state tuition or mention preference or a guarantee for state residents; not published.
• Aid: Caltech is need-blind for domestic students (including undocumented and DACA students who graduate from a US high school) and meets 100% of demonstrated need. It does not award merit scholarships; aid is need-based, and outside scholarships are welcome. The page says most students from families making less than USD 200,000 (with typical assets) can expect a package that covers tuition, and most from families under USD 100,000 can expect a no-loan package covering tuition, fees, housing and food. For the incoming fall 2026 class, average grant aid was just under USD 69,000.
• Department scholarships: the physics undergraduate page has a link to student prizes and awards that was not read. SURF provides paid summer research (section 3). A physics-specific undergraduate scholarship is not published in the pages read; see the physics website or the Financial Aid Office.

7. International students

• Who is international: Caltech defines international applicants as non-US citizens or permanent residents attending secondary school outside the United States; asylees, refugees and undocumented students in the US are domestic. Apart from financial need consideration, the application and review processes are the same for all applicants.
• English: English proficiency scores are required of all international applicants unless English is your native language or the primary language of instruction in your secondary school, in which case they are strongly recommended. Accepted: Duolingo English Test, IELTS and TOEFL, taken before the application deadline. Minimums: IELTS 7 total and 7 in each area; TOEFL taken before January 21, 2026, 100 total and 25 in each area; TOEFL taken on or after January 21, 2026 (1 to 6 scale), 5 and 5; Duolingo 130 and 130. Caltech also recommends, but does not require, an InitialView conversation and writing sample, which does not replace an English test.
• Grades and documents: official transcripts listing class titles, grades and predicted grades must come directly from your school; documents not in English need the original and an English translation, and Caltech will not review an application with any part untranslated. Caltech officers are trained to understand your education system, so do not convert grades to the US system. For other curricula the site adds: IB students need Higher Level Math, GCE A-Level students need A-Level Maths, and students in India need both year X and XII state board or CBSE examinations. Students taking only STEM classes in the final two years (for example A-Level) need two English and two social studies classes in their first two years of secondary school. Two teacher letters are required, as for everyone (a student with no humanities or social science course in the last two years may substitute a teacher in another core subject).
• Aid: Caltech is need-aware for international students because the funds for them are limited, so financial need may be a factor in admission, although it commits to meeting the demonstrated need of all admitted students. If you plan to apply for aid at any time as an undergraduate you must apply when you apply for admission; if you do not apply or receive aid for the first year you may not apply for aid for any later period (exceptions may be made for citizens of Canada and Mexico), and if aid is offered for the first year you may reapply each year. The application includes an International Financial Aid Statement of Intent.
• Proof of funds and credential evaluation: the pages read do not describe them; not published. Ask Admissions.

8. Applicants from China

• Gaokao: the pages read do not say whether or how Gaokao results are used; not published. Ask Admissions.
• Transcripts: the general international requirement applies: official transcripts sent by the school directly (grades 9 to 11 or the international curriculum equivalent), with an English translation if not in English, and a School Report from your counselor. The pages read do not list China-specific exam-certificate or credential-evaluation requirements; not published.
• Preparation and English: if your school does not offer calculus, physics or chemistry, see the alternatives in section 4; for English scores, see section 7.
• China-specific guidance: no page for Chinese applicants was found; not published.

9. Transfer students

• Which year the pages describe: the transfer pages say the application and requirements for fall 2027 will be available in late fall and list the requirements for fall 2026 applicants, but their date table prints 2027 dates; check the latest.
• Eligibility: the catalog says applicants must have completed secondary school and then enrolled at a college or university and earned credit; Caltech admits transfer students for the fall term only (not winter or spring), does not admit them to the senior year, and students who already hold a bachelor’s degree in any subject are not eligible. Transfer students enter as second- or third-year students.
• Dates: applications close February 1, 2027; entrance exams are due February 15; decisions come by mid-April (the catalog says early May, so the two pages differ); the reply deadline is June 1. Transfer admission is non-binding and non-restrictive.
• Materials: the transfer application, a USD 85 fee, math and physics entrance examinations, two college faculty letters (math, science or engineering professors), official transcripts from all colleges and your secondary school, and descriptions of all college-level math and science courses. The catalog says transfer applicants are not required to submit SAT scores and Caltech will not review any SAT or ACT scores.
• Preparation and the entrance exams: the site says transfer students are presumed to have mastered the first-year core: calculus of one and several variables, linear algebra, classical mechanics, electromagnetism and statistical physics, and special relativity. Caltech looks for these on your transcript and measures preparation through the entrance exams. After applying and after the February 1 deadline, you submit a self-proctor form in the applicant portal and receive the exams electronically; each has a 4-hour limit (8 hours in total, not necessarily on one day), taken on your honor under the Honor Code, with no reference materials, calculators or electronic devices. The site provides sample questions and a textbook list (both PDFs).
• Credit: after admission Admissions gives a preliminary estimate of class standing; after enrolling, the registrar and faculty review your transcripts and syllabi to determine credit, and Caltech cannot say before admission whether coursework elsewhere will be accepted. The catalog also says transfer students must spend at least two years (six terms) in residence, earn at least 216 units at Caltech not counting math and science core courses, and take or have the equivalent of all core courses.
• International transfer students: English proficiency requirements are as in section 7 (the transfer page lists TOEFL as total 100 and 25 in each area). No financial aid is available to international transfer and 3/2 applicants, who should expect to cover the full cost. Translations must be made by an official translator, not by the applicant.
• The 3/2 Dual Degree Plan: the catalog says Caltech invites students from a select group of liberal arts colleges to transfer after their junior year; after two years in residence and completing Caltech’s requirements they receive a Caltech BS and a second bachelor’s degree from their college, and may enter any option.

Checklist

Domestic students:

• Four years of math including calculus, a year of physics and a year of chemistry in high school; apply by November 1, 2026 (REA) or January 4, 2027 (RD)
• Take the SAT or ACT (before November 30 or December 31) and ask two teachers for letters, one STEM and one humanities or social science
• Take the common first-year core and declare the physics (or applied physics or astrophysics) option at the end of the first year

International students (including those from China):

• Same dates and materials; submit English scores as required; apply for aid at the same time as admission if you will ever need it
• Ask Admissions how Gaokao results are used and what proof of funds is needed; ask the physics department how AP and IB physics results are handled

Transfer students:

• Have earned college credit; check the latest fall 2027 requirements; apply by February 1, 2027 and return the math and physics entrance exams by February 15

Sources: Caltech, Majors and minors; The first year; Academic requirements; First-year application requirements; Deadlines; Standardized tests; International applicants; Transfer deadlines; Transfer requirements; Transfer entrance exams; International transfer applicants; Afford; Costs; Physics: undergraduate studies; Physics: FAQs for prospective undergraduates; PMA: Summer Undergraduate Research Fellowships; Catalog: Physics option; Catalog: Applied Physics option; Catalog: Astrophysics option; Catalog: core requirements; Catalog: first-year admission; Catalog: transfer admission. Dates are for fall 2027 entry and costs for 2026-27; the transfer pages describe fall 2026 requirements and the first-year academic requirements page says “fall 2026”, so check whether anything changes for fall 2027. Check Caltech’s website for the latest.