The Hampshire College Summer Studies in Mathematics (HCSSiM): Our Review
Updated: Sep 11
Updated: September 11, 2026
TL;DR
HCSSiM is a six-week residential summer program in college-level math held at Hampshire College in Massachusetts, and it's one of the most respected proof-based math programs a high schooler can attend. The 2026 session cost $7,208, though the program is free for domestic families earning under $85,000 and offers aid on a sliding scale above that. HCSSiM doesn't publish a formal acceptance rate, but its own 2025 numbers (1,100+ applicants, 51 attendees) put it at roughly 4-5%. The biggest change since our last update is that Hampshire College, which has hosted HCSSiM since 1971, is permanently closing in December 2026, but HCSSiM itself became a financially independent nonprofit back in July 2025 and will keep running, just at a still-to-be-announced new campus starting in 2027. If you want a research-based alternative or complement to a coursework-heavy program like this one, Lumiere's Research Scholar Program pairs high schoolers with a PhD mentor to write an independent research paper.
If you're a high school student who's serious about mathematics and looking at prestigious summer programs, you've probably already come across HCSSiM. It's one of the oldest and best-regarded summer math programs in the country, alongside options like PROMYS, MathILy, and the Ross Mathematics Program.
Before you apply anywhere, you should weigh the same handful of factors for any math program: curriculum, cost, location, selectivity, and faculty. This review covers all of that for HCSSiM, plus what's changed heading into 2026 and 2027, including a major shift in who actually runs the program.
What is HCSSiM and who is it for?
HCSSiM has run most summers since 1971, when Hampshire College mathematician David Kelly founded it. The program puts high schoolers through college-level mathematics for six weeks, prioritizing collaborative, proof-based problem-solving over a fixed syllabus. Students spend roughly four hours each morning in workshops, an evening problem session most nights, and a daily "Prime Time Theorem" talk, with afternoons left for recreation, informal study, and campus life.
Kelly directed the program until his death in June 2025. Paul Phillips, a Senior Staff member and University of Dallas math professor who has taught at HCSSiM since 2013, is now serving as Interim Director on an initial three-year contract.
HCSSiM suits a specific kind of student: someone who already has some exposure to advanced math and genuinely wants to spend a summer doing more of it, not primarily to pad a college application. If your goal is original research output rather than coursework, a research-based program is probably a better fit than HCSSiM.
What's happening with Hampshire College's closure?
This is the update that matters most for anyone researching HCSSiM right now. Hampshire College announced it will permanently close after the fall 2026 semester, but HCSSiM will keep running regardless, because it's no longer part of the college. On July 1, 2025, HCSSiM's operating nonprofit, the Yellow Pig Math Foundation, and Hampshire College finalized a multi-year contract that made the Foundation financially and operationally independent of the college.
The 2026 session (its 54th) ran as planned on Hampshire's campus from June 28 to August 8, 2026. What comes next is genuinely unresolved: as of this writing, HCSSiM has not announced a new host campus for 2027, and its own site says details will come in late 2026.
How much does HCSSiM cost, and what financial aid is available?
The 2026 session costs $7,208, up from $6,511 in 2025 and $5,780 a few years before that. That fee covers tuition, room, three meals a day for six weeks, local transportation to and from bus, train, and airport connections, and recreational activities, but not personal spending money or travel to Amherst itself.
HCSSiM's aid is unusually generous for a program this selective. The table below reflects 2025 figures (2026 figures weren't posted at the time of writing):
Annual household income | Minimum payment | Maximum payment |
$0–$85,000 | $0 + travel grant | $0 |
$85,001–$119,000 | $0 + travel grant | $1,700 |
$119,001–$153,000 | $170 | $3,400 |
$153,001–$187,000 | $510 | $6,511 |
$187,000+ | Case-by-case | Case-by-case |
International students are eligible for aid too, decided case by case. Aid decisions are confidential and made after admission, so they don't affect who gets in.
What is HCSSiM's acceptance rate?
HCSSiM doesn't publish a formal acceptance rate, but the Yellow Pig Math Foundation's own November 2025 letter to alumni gives real numbers for the 2025 cohort: more than 1,100 students applied, more than 700 completed the Interesting Test, and 51 ultimately attended, for roughly 4-5% of all applicants (closer to 7% if you count only students who finished the test). That's up from about 1,000 applicants the year before, so the program has gotten more competitive, not less. 2026 cohort numbers aren't out yet; expect them in the foundation's next annual letter, typically posted in November.
What do you actually study at HCSSiM?
The first three weeks are workshops, taught by a faculty member and one or two math majors or grad students, running four hours each weekday morning and two hours Saturday morning, plus an evening problem session most nights. Workshop content commonly covers most of an undergraduate elementary number theory course, most of a combinatorics or graph theory course, and part of a modern algebra course.
After that, students choose one maxi-course (equivalent to a full-semester undergraduate elective) and two mini-courses. Recent maxi-courses have covered topics like Shannon's information theory, iteration and chaos through fractals, axiomatic probability theory, and surreal numbers, while mini-courses have ranged from knot theory and Galois theory to cryptography and algebraic topology. Course offerings change year to year based on which faculty are teaching, so treat any specific list as illustrative rather than guaranteed.
What does a typical day look like?
Mornings are workshop or maxi/mini-course time. Lunch is shared with faculty. Afternoons are unstructured: reading, recreation, informal study, or occasional trips into town. Evenings bring a problem session and, most days, the Prime Time Theorem, a roughly hour-long talk on a mathematical topic, often given by a visiting mathematician.
Who is eligible to apply?
HCSSiM has no official age or grade cutoff, but most students have just finished 9th, 10th, or 11th grade, and admission is not open to students who have already graduated high school. International students are welcome and make up a meaningful share of the cohort (5 countries represented in 2025).
One eligibility-adjacent detail worth knowing: HCSSiM requires applicants to affirm they did not use AI to write any part of their application, including the required "Friendly Letter." The program says it welcomes brainstorming help, proofreading, and disability accommodations, but the letter itself has to be the student's own writing.
No transcript or standardized test score is required. Instead, admission runs on the application form, a "Friendly Letter" about why you want to attend, a sponsor's recommendation, and the Interesting Test (a set of open-ended math problems).
2026 application timeline
Applications run on a rolling basis with no hard deadline, but HCSSiM sets an informal cutoff once it has enough strong applications for the year. Here's how the 2026 cycle actually played out, as a reference point for what to expect (2027 dates have not been announced):
Milestone | 2026 date |
Applications open | Rolling; no fixed open date published |
Interesting Test emailed to applicants | Mid-to-late March 2026 |
Cutoff for new applications | April 17, 2026 |
Interesting Test due | April 25, 2026 |
Admission decisions | Rolling, after Interesting Test review |
Program dates (54th session) | June 28 – August 8, 2026 |
How do you apply to HCSSiM?
Fill out the online application, including a Friendly Letter about why you want to attend and the name of a sponsor who can speak to your mathematical ability.
You'll get a confirmation email with a link to that year's Interesting Test, usually sent mid-to-late March.
Complete the Interesting Test and return it by the posted deadline (April 25 for the 2026 cycle).
Wait for a rolling admission decision.
Tips for a strong application
Start the Interesting Test as soon as you get it. It's designed to take real time and reward sustained thinking, not a quick answer.
Draft your Friendly Letter separately before pasting it into the form, per HCSSiM's own advice, so you don't lose your work.
Pick a sponsor who actually knows how you think about math, not just whoever has the most impressive title.
Write the Friendly Letter yourself. HCSSiM explicitly asks you to affirm you didn't use AI on it, and a letter that doesn't sound like a 16-year-old wrote it is a red flag, not an asset.
Apply as early in the cycle as you reasonably can. Application volume has grown every year on record, and the informal deadline moves up as the program fills.
Is HCSSiM worth it?
HCSSiM is a genuinely rigorous, well-regarded program, and its emphasis on proof-based thinking over rote competition math is one of the things that sets it apart from more competition-prep-oriented summer options. Its alumni network is unusually strong for a high school program: two MacArthur Fellows, two Morgan Prize winners, an AMS Fellow class induction for its own founder, and a long list of graduates now teaching math, computer science, and physics at the university level.
The tradeoffs are real, though. Six weeks is a meaningful chunk of a summer, the $7,208 sticker price is steep before aid, and the program leans academic rather than research-output-focused, so it won't produce a paper or project you can point to the way a research program would. If you want that kind of deliverable alongside (or instead of) a coursework-heavy summer, a mentored research program is worth comparing against HCSSiM directly. Students weighing similar options often also look at PROMYS, MathILy, or the Ross Mathematics Program, and if you're casting a wider net, our roundup of 10 math programs for high school students is a reasonable starting point. Students who want to pursue Intel, Siemens, or similar competitions after HCSSiM may also want to look at our list of online math competitions for high school students.
Frequently asked questions
What is HCSSiM? HCSSiM (the Hampshire College Summer Studies in Mathematics) is a six-week residential summer program in college-level math for high school students, run by the nonprofit Yellow Pig Math Foundation. It's been held most summers since 1971 and emphasizes proof-based, collaborative problem-solving over a fixed curriculum.
How much does HCSSiM cost in 2026? The 2026 session costs $7,208, covering tuition, room, three meals a day for six weeks, local transportation, and recreational activities. The program is free for domestic families with household income under $85,000, with aid available on a sliding scale above that.
What is HCSSiM's acceptance rate? HCSSiM doesn't publish an official acceptance rate. Its own 2025 figures show more than 1,100 applicants and 51 attendees, which works out to roughly 4-5% of all applicants, or about 7% of the students who completed the Interesting Test.
Is HCSSiM affected by Hampshire College's closure? No, not operationally. HCSSiM became financially and legally independent of Hampshire College in July 2025, so it will keep running after the college's planned closure in December 2026. It just needs a new host campus starting in 2027, which hasn't been announced yet.
What is the HCSSiM Interesting Test? The Interesting Test is HCSSiM's admissions exam: a set of open-ended math problems emailed to applicants, typically in mid-to-late March. It replaces transcripts and standardized test scores and is meant to show how you think through a problem, not just whether you get the right answer.
Is there an age or grade requirement for HCSSiM? HCSSiM has no official age cutoff, though most students have just finished 9th, 10th, or 11th grade with some background in advanced math. Students who have already graduated high school are not eligible to apply.
Can international students apply to HCSSiM? Yes. International students are welcome to apply and are eligible for need-based financial aid, though most students each year still come from the US (18 states and 5 countries in the 2025 cohort).
Is HCSSiM worth it for college applications? HCSSiM is a strong signal of genuine mathematical interest, but no single summer program decides an admissions outcome on its own. It's most worth it if you actually want six weeks of intense, proof-based math, and if you want a research paper to show for your summer instead, a program like Lumiere's Research Scholar Program is a more direct fit.
Stephen Turban is the co-founder of Lumiere Education and a graduate of Harvard College, where he earned an A.B. in Statistics before beginning a PhD at Harvard Business School. A former McKinsey & Company consultant and former researcher, his research has been covered by the Harvard Business Review, The Economist, BBC News, Freakonomics Radio, and the Washington Post. In his articles for Forbes, he writes on what students and professionals can learn from high school research, high school passion projects, critical thinking, and mentorship. At Lumiere, he leads a selective research program where students work one-on-one with a research mentor to develop an independent research paper. Connect with him on LinkedIn.