With an admission rate under 4 percent, Caltech is one of the most selective universities in the world. Known for its unparalleled research opportunities and small, collaborative community, Caltech attracts some of the most talented STEM minds from across the globe. Thousands of students apply each year for the chance to study at a place where curiosity, innovation, and academic rigor meet.
The Caltech application includes a set of supplemental essays that give you the opportunity to share your personality, passions, and fit for the Institute. Each question is a chance to show how you think, what excites you, and how you will contribute to Caltech’s unique environment.
To help you through the writing process, here is InGenius Prep’s guide to the Caltech supplemental essays.
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Caltech Supplemental Essays
1. Your STEM Future – Academic Interests
If you had to choose an area of interest or two today what would you choose? Why did you choose your proposed area of interest? If you selected “other,” what topics are you interested in pursuing? (100–200 words)
This is your “Why this major?” moment. Start with the spark, what got you hooked? Maybe you were fascinated by space after seeing images from the James Webb Space Telescope, or drawn to bioengineering after reading about CRISPR technology. Then bridge your story to Caltech’s offerings.
Caltech is small but has outsized research power. If you are into planetary science, reference the Infrared Processing and Analysis Center or the Owens Valley Radio Observatory. For quantum computing, look into the Institute for Quantum Information and Matter. Mention professors, research groups, or ongoing projects you want to learn from. Caltech admits students who know what they want and understand how Caltech will help them achieve it. The more precise your connections, the more convincing your essay will be.
2. Your STEM Present – STEM Curiosity
Regardless of your STEM interest listed above, take this opportunity to nerd out and talk to us about whatever STEM “rabbit hole” you have found yourself falling into. Be as specific or broad as you would like. (50–150 words)
Caltech wants to see curiosity that exists outside of grades or assignments. This could be a niche subject you chased down just because you wanted to know more, like the fluid dynamics of jellyfish propulsion or the mathematics of origami engineering.
Show how you explored it. Did you code simulations? Build a prototype? Spend hours reading research papers well above your grade level? Bonus points if you can tie it to Caltech’s work, such as a fascination with earthquake modeling connected to research at Caltech’s Seismological Laboratory. Keep it concise but vivid so the reader can feel your excitement.
3. Your STEM Past – STEM Experiences
a) Tell us how you initially found your interest and passion for science or for a particular STEM topic and how you have pursued or developed your interest or passion over the last few years. (100–200 words)
b) Tell us about a meaningful STEM-related experience from the last few years and share how and why it inspired your curiosity. (100–200 words)
Here you get two opportunities to show growth.
For part (a), think origin story. Maybe you dismantled your first computer at 12 or stayed after class to build a makeshift spectrometer with your physics teacher. Show the link between that early moment and your more recent steps, such as summer programs, competitions, or internships that have refined your skills.
For part (b), pick an advanced or recent experience that pushed you further. Perhaps you participated in a machine learning research project at a local university or built an autonomous drone for a robotics competition. Do not just list the experience, explain why it deepened your curiosity. Then connect it to how you could grow further at Caltech, perhaps through the Summer Undergraduate Research Fellowships (SURF) program or by joining a specific lab.
4. Creativity in Action
How have you been a creator, inventor, or innovator in your own life? (200–250 words)
Caltech thrives on creative problem-solvers. Your story could be about inventing a low-cost water purification system, designing a novel algorithm, or reimagining your school’s waste management process. The scale does not matter, impact and process do.
Break it down. What problem were you addressing? How did you brainstorm solutions? What obstacles did you face, and how did you overcome them? Caltech values students who iterate, test, fail, and improve. If relevant, tie your example to how you would continue this work at Caltech. For example, mechanical tinkerers might connect with the ME72 Engineering Design Competition, while coders might reference collaborations with the Center for Data-Driven Discovery.
5. Caltech Values – Diversity of Thought
Caltech values respect for a diversity of thoughts and ideas. How have you cultivated this value in your own life? (50–200 words)
Caltech’s breakthroughs often come from interdisciplinary teamwork. Show that you are prepared for this. Maybe you were part of a multi-school hackathon team with very different skill levels, or you collaborated with artists to visualize complex data. Focus on what you learned from others’ perspectives and how it improved your own thinking.
If you have an example where listening changed your approach, such as adopting a biology-based method to solve a physics problem, highlight that. This demonstrates that you are ready for Caltech’s culture of respectful debate and shared problem-solving.
Short Answer Set – Choose Two (Combined Total: 250 Words)
Choose any two of the following prompts and answer both in 250 words or fewer (combined total):
- What is an interest or hobby you do for fun and why does it bring you joy?
- If you could teach a class on any topic or concept, what would it be and why?
- What is a core piece of your identity or being that shapes how you view and/or interact with the world?
- What is a concept that blew your mind or baffled you when you first encountered it?
These short responses let you fill in the non-STEM parts of your personality.
If you choose the hobby question, show what it reveals about you. Astronomy photography might connect patience with artistic vision. For the “teach a class” prompt, you could blend disciplines, such as “The Physics of Music,” and explain why the intersection matters to you.
The identity question is your chance to talk about values or experiences that shape your worldview. The “concept that blew your mind” could be tied to Caltech’s research, such as quantum entanglement or the idea of programmable matter. These are small spaces, so every sentence should add a new facet to who you are.
Additional Tips for Writing the Caltech Supplemental Essays
- Avoid repetition. Each essay should highlight a different aspect of your experience or personality.
- Be specific. Use vivid examples and reference Caltech programs, professors, labs, or clubs.
- Show your process. Caltech values how you think, not just what you have accomplished.
- Let your personality shine. Authenticity stands out in a highly competitive pool.
The key takeaway for the Caltech supplemental essays is that Admissions Officers want to understand how you think, what excites you, and how you will contribute to the Caltech community. Keep these ideas in mind as you approach each prompt.
If you are looking for more help on your supplemental essays and other writing materials, InGenius Prep is here to help. Our team of Former Admissions Officers from top schools like Caltech know exactly what admissions offices are looking for. Book a free strategy call today and become one of the 6,000 students we have helped get an acceptance letter from their dream school!