Five million users. Eight-figure annual recurring revenue. Twenty thousand new users joining daily. These are some solid numbers for a startup called Turbo AI launched in early 2024 by Rudy Arora and Sarthak Dhawan, two 20-year-old college dropouts.

Most of this growth has come in the past six months, the founders tell TechCrunch, during which their AI-powered note-taking and study tool grew from one million to five million users, while remaining profitable.

They say the idea for Turbo stemmed from a classroom problem many college students face, which is trying to take notes while paying attention to a lecture at the same time.

“I would always struggle with taking notes because I just couldn’t both listen to the teacher and write at the same time. I just couldn’t do it,” said CEO Dhawan. “Every time I tried to take notes, I’d stop paying attention. And when I listened, I couldn’t take notes. I was like, what if I could use AI?”

So the pair built Turbolearn as a side project to allow them to record lectures and automatically generate notes, flashcards, and quizzes. They began sharing it with friends, then it spread to classmates across Duke and Northwestern, where they were enrolled until dropping out this year. Within months, the app had reached other universities, including Harvard and MIT.

The product takes the usual note-taker formula—record, transcribe, summarize—and makes it interactive with study notes, quizzes, and flashcards, along with a built-in chat assistant that explains key terms or concepts.

However, recordings in large halls often pick up background noise, so the founders built features that allow students to upload PDFs, lectures, YouTube videos, or readings instead. That’s now a more common use case than live lecture recordings.

“Students will upload a 30-page lecture and spend two hours going through 75 quiz questions in a row. You don’t do that unless it’s really working,” said Dhawan, noting that students love how the product saves time and helps them retain information.

It’s not just students using Turbo AI, though—as reflected by the name change from Turbolearn (a study app) to Turbo AI (an AI notetaker and learning assistant). Professionals have adopted it too, including consultants, lawyers, doctors, and even analysts at Goldman Sachs and McKinsey, the founders say. Some, for instance, upload reports and use Turbo to generate summaries or convert them into podcasts they can listen to on their commute.

Arora and Dhawan have been friends since middle school and have collaborated on multiple projects over the years.

Dhawan previously built UMax, an advice app that promised to make people more attractive and reached #1 on the App Store with 20 million users and $6 million in annual revenue. Arora, meanwhile, specializes in using social media strategies to drive explosive growth and attract millions of users.

Building viral apps is a rare skill. But despite the scale of their previous projects, the founders only felt the need to drop out for Turbo because they saw an opportunity to build a lasting business.

Still, unlike many fast-growing AI companies, they’re cautious about raising too much money too early, having taken in only $750,000 last year.

“We raised that before we had a lot of traction. Since then, we’ve had a lot of inbound interest, but we’re taking our time because we’re cash-flow positive and have been profitable our entire time as a company,” said Arora, who added that their 15-person team is based in Los Angeles and focused on staying close to student and creator communities at colleges like UCLA.

Students pay about $20 a month for the product, but the founders say they’re exploring other pricing options to reflect the price sensitivity of students, even as the app scales beyond the target group. “Right now, we’re experimenting with other pricing and running a lot of A/B tests to see what works,” Arora added.

Turbo AI sits between fully manual tools like Google Docs and fully automated note-takers like Otter or Fireflies. Users can let the AI take notes or write alongside it, the founders say. That approach has helped Turbo stand out even as competitors like Y Combinator–backed YouLearn target similar student audiences.

“What’s cool now is that when students think of an AI notetaker or AI study tool, we’re the first ones that come to mind,” Dhawan said.