Caltech Supplemental Essays 2025-26 – Prompts & Advice

June 26, 2025

With an acceptance rate of less than 3% (yes, truly), Caltech is one of the most highly selective schools in the country. Although ACT or SAT results are now required again during the admissions process, the Caltech admissions committee does give serious weight to the six supplemental essay prompts that they require from all applicants.

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Before we dive right in and begin examining the six required 2025-26 Caltech essays, one quick note…the admissions committee has provided in-depth guidance for all six, so we’ll keep our advice for those short and sweet.

Caltech Supplemental Essays – 2025-26

Prompt #1 (required)

Why did you choose your proposed area of interest? If you selected ‘other’, what topics are you interested in pursuing? (100-200 words)

(Note: you’ll select 1-2 areas of interest from a provided drop-down box on the application)

We all have a story of what drives us to pursue a certain academic pathway and career. How did your interest initially develop? What was the spark? How have you nurtured this passion and how has it evolved over time? If you desire to go into engineering, this is a chance to talk about everything from your childhood fascination with how things work to your participation in an award-winning robotics program at your high school. Share a compelling (and, of course, true!) narrative about how your love of your future area of study has blossomed to its present levels.

For this Caltech supplemental essay, you should also tie your passions into specific academic opportunities such as courses, professors, hands-on research programs, or any other aspects of your desired major that appeal most to you.

Prompt #2 (required)

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)

Can you think of a recent time when you have been completely sucked into a STEM-related topic? Perhaps you binged every documentary available, consumed podcasts like nobody’s business, went on a Reddit bender, or found the most fascinating book at the library. What do you find so interesting about this topic, and why?

While your “rabbit hole” doesn’t necessarily have to lead to anything actionable, you can certainly mention if it did. For example, if your fascination inspired you to take on a particular project—which helped you learn even more about your subject—that could be an excellent addition to your answer.

Prompt #3 (required)

At Caltech, we investigate some of the most challenging, fundamental problems in science, technology, engineering, and mathematics. We are interested in learning more about your engagement with STEM.

Select one of the following two STEM Experience prompts to respond to (100-200 words):

1. 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.

2. Tell us about a meaningful STEM-related experience from the last few years and share how and why it inspired your curiosity.

Main note here—you’ll be choosing just one of these prompts to respond to. For both, you’ll want to get as specific and recent as possible (notice the “from the last few years” language), but there are several key differences. Choose Prompt #1, and you’ll discuss how you discovered your interest and how you’ve recently pursued it. Select Prompt #2, and you’ll focus on just one particularly meaningful experience.

Wondering which to choose? Prompt #1 will likely be best for students who have a long history with a particular STEM area or subject—and potentially more than one recent experience they’d like to share—while Prompt #2 might be a better fit for students who can point to a singular standout experience that inspired them to learn more.

Whether you experienced a fascinating challenge during your engineering internship, encountered a particularly thought-provoking topic during differential calculus, or have relentlessly pursued an interest in black holes since you were ten, choose the option that best allows you to capture your most significant experiences and present yourself as a sincerely curious young person with a strong intellectual drive.

Prompt #4 (required)

The creativity, inventiveness, and innovation of Caltech’s students, faculty, and researchers have won Nobel Prizes and put rovers on Mars. But Techers also innovate in smaller-scale ways everyday, from imagining new ways to design solar cells or how to 3D-print dorm decor, to cooking up new recipes in the kitchen. How have you been a creator, inventor, or innovator in your own life? (50-150 words)

Caltech knows you’re not a PhD-level researcher or a Nobel laureate, so they’re not looking for anything earth-shattering here (unless, of course, you’ve accomplished something earth-shattering—in which case, please share). Instead, they’re simply trying to understand the ways in which you bring your creative, inventive, and/or innovative qualities to your day-to-day life. Essentially, this Caltech supplemental essay is a fun chance to show off that side of yourself. To do so, feel free to go beyond extracurricular activities and formal experiences—maybe you perfected a solar oven design that bakes perfectly chewy chocolate chip cookies without utilizing electricity, or offered to develop a website for your local thrift shop with online shopping options. The sky is the limit here!

Prompts #5 & #6 (required)

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 about a core piece of your identity.

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?
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?

Caltech has replaced its long-time set of optional essays about interests & hobbies with several required responses. There are four options, and you’ll need to choose two. Fortunately, these supplemental essays are short—Caltech wants you to stick to just 250 words between both responses—so look at them as a way to fill in any final gaps, share something significant about your background or identity that has not been discussed elsewhere, or reinforce your interests.

How important are the Caltech supplemental essays?

Overall, Caltech lists five factors as being “very important” to the admissions process. Those factors are: the rigor of your high school coursework, test scores (they recently reinstated their testing requirements), recommendations, character/personal qualities, and your application essays. In fact, the essays are rated as being of greater importance than your GPA, class rank, or extracurricular activities!

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College Admissions

Dave Bergman

Dave has over a decade of professional experience that includes work as a teacher, high school administrator, college professor, and independent educational consultant. He is a co-author of the books The Enlightened College Applicant (Rowman & Littlefield, 2016) and Colleges Worth Your Money (Rowman & Littlefield, 2020).