California Institute of Technology, also known as Caltech, is a renowned university that focuses on providing a rigorous STEM education to its students. Caltech’s living alumni include 17 Nobel Laureates, such as Richard Feynman. Other notable Caltech alumni include Stephen Wolfram, Fei-Fei Li, Adam D’Angelo, and David Brin. If you’re an aspiring Techie, you’ve come to the right place. The Caltech supplemental essays include six required and four optional prompts for prospective applicants to answer. Let’s dive in.
Caltech’s 2025-2026 Prompts
Required Caltech Supplemental Essays
- Your STEM Future – STEM Academic Interests: Caltech has a rigorous core curriculum and students don’t declare a major until the end of their first year. However, some students arrive knowing which academic fields and areas already most excite them, or which novel fields and areas they most want to explore. 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)
- 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)
- Your STEM Past – STEM Experiences: Tell us how you initially found your interest and passion for science or any STEM topic, and how you have pursued or developed this interest or passion over time. (100-200 words)
- Your STEM Past – STEM Experiences (continued): 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)
- Creativity in Action Question: The creativity, inventiveness, and innovation of Caltech’s students, faculty, and researchers have won Nobel Prizes and put rovers on Mars. But Techers also imagine smaller-scale innovations every day, from new ways to design solar cells to how to 3D-print dorm decor to experimenting in the kitchen. How have you been a creator, inventor, or innovator in your own life? (200-250 words)
Required Caltech Supplemental Essays
- 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?
Optional Caltech Supplemental Essays
- Have you had any extenuating circumstances (such as limited course selection or disruptions), that have affected your coursework, but that are not described elsewhere in your application? If so, tell us about them here.
General Tips
While Caltech is unusual in offering ten essay prompts for applicants to answer, these essays don’t have to be difficult. Before you begin writing the first essay, read through all the prompts. That way, you can pace yourself. If a topic has multiple facets that could be discussed in different essays, versus getting jammed into one essay, then go for it. What might seem like an excessive number of essays to write is actually just an abundance of opportunities to show Caltech who you are.
Moreover, the optional essay prompts are really just that: optional. In order to be effective and boost your chances of admission, your Caltech supplemental essays need to be thoughtful, organized, proofread, and specific. If you only have the bandwidth to bring your best writing talents to the required prompts, you should feel no pressure to write a few more rushed essays. In addition, not all of the optional prompts will relate to all applicants. In other words, don’t try to write responses to the optional prompts if they don’t speak to you. Instead, consider all of the parts of yourself you’d really like Caltech to know, and do your best to incorporate them into the essays you are required to write.
That said, let’s dive in.
Required Caltech Short Essay Questions
Your STEM Future – STEM Academic Interests: Caltech has a rigorous core curriculum and students don’t declare a major until the end of their first year. However, some students arrive knowing which academic fields and areas already most excite them, or which novel fields and areas they most want to explore. 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)
Although you’re not bound to study whatever major or area of interest you describe in this essay, you should answer authentically. Through the Caltech supplemental essays, the admissions team seeks curious, driven individuals who already know they want to pursue STEM. Because of this, you’ll want to let your passion shine through.
In addition, whether you have a particular origin story behind your academic interest(s), or you simply enjoy pursuing the questions behind your interest(s), this essay response will benefit from specific details. For example, you hope to study computer science, explain to the reader what kind of computer science you’re interested in, how you became interested in this subfield, and, if you have space, what you hope to do with this degree. Don’t be afraid to sound nerdy!
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)
If there were any details or interests you couldn’t fit into the answer above, here’s your opportunity to explore them further. Note that the wording of the prompt indicates that you should only discuss one rabbit hole in this essay. Instead of discussing all your interests in one place, focus on one topic you’ve regularly been Googling, reading about, watching YouTube videos on, or otherwise researching. Remember, there are quite a few Caltech essays. Therefore, you should aim for depth instead of breadth in this essay. Any topics you wish you could have addressed here, you’ll likely have the opportunity to address in another essay.
Your STEM Past – STEM Experiences: Tell us how you initially found your interest and passion for science or any STEM topic, and how you have pursued or developed this interest or passion over time. (100-200 words)
This essay prompt has some overlap with the first prompt, which could also involve the origin story of a STEM interest of yours. That said, this prompt could be about any STEM interest, not just your intended area of study. In addition, you could focus this essay on a more specific interest, topic, or subfield than your area of study. In fact, you could focus on a singular, specific topic that is included within your area of study. You could even get as specific as a single question you’ve sought to answer over the years.
If you’re having trouble coming up with topics for this essay, consider focusing on whatever interest has the best story behind it. Note that the prompt expects a singular topic, not multiple topics. This prompt expects you to provide the past, present, and future of a particular interest. Therefore, if you have been pursuing any particular topic for a while, then that topic might fit well into this essay.
Your STEM Past – STEM Experiences (continued): Tell us about a STEM-related experience from the last few years and share how and why it inspired your curiosity. (100-200 words)
This prompt, which is under the same subheading as the previous prompt (”Your STEM Past – STEM Experiences), opens the door for you to discuss extracurricular activities or coursework. For instance, you could describe a lab project in school that inspired your interest in biology. You could focus on an independent research project you have pursued, a summer camp you have attended, a lecture you have heard, or even a book you have read.
The prompt asks you to discuss an “experience,” so be sure to keep your narrative concrete, not abstract. Your essay should clarify that the topic of your essay involved a real-life experience. Then, you should explore how that experience has impacted you and your interest(s).
Creativity in Action Question: The creativity, inventiveness, and innovation of Caltech’s students, faculty, and researchers have won Nobel Prizes and put rovers on Mars. But Techers also imagine smaller-scale innovations every day, from new ways to design solar cells to how to 3D-print dorm decor to experimenting in the kitchen. How have you been a creator, inventor, or innovator in your own life? (200-250 words)
This essay is your space to describe a project you’ve undertaken, a way you’ve optimized your daily life, a practical idea you’ve come up, or something along these lines. The more creative, the better. Consider the times when you’ve worked with your hands, solved practical problems for your family or friends, or used your technical skills to create something new and unexpected.
The admissions team set this prompt in order to gauge their applicants’ level of creativity and drive to be industriousness in their daily lives. Creativity is great to demonstrate here, but you can also highlight the ways you’ve served others. Not only will you be a student at Caltech, but you will be a peer, a roommate, a community member, and a friend. Therefore, if you have created, invented, or innovated on behalf of others, then you might want to focus on one of those projects here.
Required Caltech Short Answer Questions
Now it’s time for a little fun! Choose two of the four questions below and answer both in 250 words or less. It’s up to you how you use your 250 words, whether that means you use exactly 125 words for each answer or you tell us about a niche interest in 30 words so you can spend 200 telling us more about you.
There is no ‘right’ way to choose which question to answer. If you’re all STEMmed out, feel free to tell us about a creative hobby. Or if you just can’t get enough math, tell us about a concept you can barely wrap your head around. Just remember the Caltech Honor Code and stick to 250 words for both answers combined.
What is an interest or hobby you do for fun, and why does it bring you joy?
The key word in this prompt is “joy.” While brainstorming for this prompt, think about the ways you spend your time. When are you most joyful? What excites you? What do you look forward to doing in your spare time? Here’s your opportunity to elaborate on a source of joy for you.
A “favorite interest or hobby,” in the context of this prompt, should be something that you do simply because you like to. In other words, this activity should not be solely driven by your desire to pad your resume, earn money, or please your parents. This activity should be self-driven and self-motivated.
In addition, this should be a singular activity. Because most people can write at lengths about their passions, it is important to keep this essay focused on one topic, with a clear beginning, middle, and end. Before you begin to write, consider structuring your essay around an anecdote. You could also write this essay about how your interest/activity/hobby has changed you as a person, a structure which would give your essay a clear narrative arc. However you choose to organize your thoughts in this essay, pay attention to the narrative structure, make sure every sentence relates back to your overarching topic, and be sure to let your joy shine through.
If you could teach a class on any topic or concept, what would it be and why?
This prompt is asking you about your intellectual passions through the lens of sharing this knowledge with others. The “teaching” angle is key here! It’s not just asking about what you’re interseted in, but what you’re excited enough about to want to share with others.
When brainstorming, think beyond traditinoal academic subjects like calculus or American history. Perhaps you’re interested in “The art of storytelling in video games,” but it also doesn’t have to be STEM-focused. The key is choosing something you genuinely know well and feel passionate about sharing.
Also, consider what makes you the right person to teach this particular topic. Maybe you’ve spent years mastering a skill, had unique experiences that gave you insight, or approached a subject from an unconventional angle. The “why” part of the prompt is crucial as admissions officers want to understand both your expertise and your motivation to share your knowledge.
Structure-wise, you might start with a specific moment that crystallized your desire to teach this topic, or jump right into describing your hypothetical classroom and teaching methods. Either way, make sure your genuine enthusiasm comes through, and be specific about what exactly you would cover and how you would make it engaging for students.
What is a core piece of your identity or being that shapes how you view and/or interact with the world?
Like all of the Caltech supplemental essays, this prompt provides applicants with the opportunity to discuss topics otherwise unmentioned in their applications. For instance, if your Caltech application explores your academic and extracurricular interests and achievements but ignores your cultural identity, you might want to write about that topic in this essay. In other words, if there are parts of who you are and how you present yourself to the world that aren’t addressed elsewhere in your application but feel important to you to mention, here’s your chance.
The word “identity” can be treated expansively here. Your identity can include your gender, ethnicity, immigration status, sexual orientation, Myers-Briggs type, political party, religion, and more. Remember, the admissions team has posed this prompt in order to get to know you better. If you were meeting someone for the first time, what would you hope they understood about you? This essay is the right place to answer that question.
However, simply identifying a core aspect of who you are isn’t enough—the prompt specifically asks how this identity piece shapes both your worldview and your interactions. You need to demonstrate how this identity acts as a lens through which you see situations, problems, and opportunities differently than others might. More importantly, you must show how it translates into action: how does it influence your behavior, your approach to challenges, your way of engaging with others, or your decision-making process? Use specific examples and concrete situations to illustrate both the perspective and behavioral changes this identity brings to your life, avoiding vague generalizations about how it “makes you more understanding” or “helps you see different viewpoints.”
What is a concept that blew your mind or baffled you when you first encountered it?
This prompt is looking for intellectual curiosity and your ability to engage with challenging ideas. The admissions committee wants to see how you react when encountering something that pushes the boundaries of your understanding.
Don’t overthink what will sound most impressive here. The concept that truly baffled you might be something relatively simple that just hit you in a profound way, or it could be something highly complex. What matters is that it genuinely affected how you think. Maybe it was learning that there are different sizes of infinity in mathematics, or realizing that colors don’t actually exist outside of our perception, or understanding how compound interest really works.
The “when you first encountered it” part suggests you should tell this as a story. Where were you? What were you doing? The narrative of discovery is often just as important as the concept itself. Make sure to clearly explain the concept itself—assume your reader doesn’t know what you’re talking about. Then explore why it had such an impact. The goal is to show that you’re someone who genuinely gets excited by learning and isn’t afraid of ideas that challenge your assumptions.
Optional Caltech Short Answer Questions
Have you had any extenuating circumstances (such as limited course selection or disruptions), that have affected your coursework, but that are not described elsewhere in your application? If so, tell us about them here.
This essay prompt gives an applicant the opportunity to bring up a topic otherwise untouched in their application. If your GPA was affected by factors outside your control, your AP exams disturbed or unexpectedly canceled, or another similar issue, then you don’t have to be burdened by that situation in your college application process. Instead, you can elaborate on your unique circumstances here, in an essay with no official word limit.
Be as specific, humble, and honest as you can be here. Moreover, don’t write more than you need to. Although there’s no official word limit on this essay, the admissions officers at Caltech are busy individuals. As briefly as you can, provide the details of your extenuating circumstances, but don’t provide more information than necessary.
If you need help polishing up your Caltech supplemental essays, check out our College Essay Review service. You can receive detailed feedback from Ivy League consultants in as little as 24 hours.
