When it comes to solving problems through simplicity, few tools have had the impact of Omni Calculator. Built on the belief that knowledge should be accessible, practical, and free, the platform now features nearly 3,700 calculators across categories like finance, health, math, chemistry, and more.
At the center of this success story is Mateusz Mucha, a founder who turned a personal learning project into a go-to global solution for millions. In this interview, Mateusz Mucha reflects on the early spark, the bold decisions, and the unwavering vision behind Omni’s growth.
Mateusz Mucha: Omni Calculator began as a hobby project you built while still in high school. What problem were you originally trying to solve, and what drew you to building calculators in the first place?
Originally, I just wanted to learn JavaScript. Back then, a lot of websites were still pretty static, and JavaScript allowed you to make something happen live on the page. I was fascinated by the potential, so to learn the language—and as a math guy—I decided to build a calculator. My first project (before the margin calculator) was a very simple percentage calculator, and the cool thing about it was that it worked both ways. You could enter any two of the three fields, and the empty one would be calculated. This is true for almost every Omni calculator to this day, and that was something quite revolutionary on the internet back then.
One of your earliest innovations was creating calculators that work in any direction, without fixed inputs or outputs. How did that idea come about, and why was it so important to you?
As I mentioned above, the main reason for it was to learn the technology that allows for creating tools on the web—JavaScript—and to create something that people would actually like to use (because who doesn’t want their work to be shared and appreciated?). The idea seems simple today, but it wasn’t very common back then, which is why the calculator gained initial traction.
In 2014, you decided to turn a side project into a real business. What made you believe Omni Calculator could become something much bigger?
When I created the percentage calculator and got some traffic from it, my friends encouraged me to make other variations, like a “percentage off calculator” or a “margin calculator” for people to calculate real-life things. Being quite new to the business game, I said it was stupid because you could calculate all those things using my existing percentage calculator. But after some time, I decided to actually create them and host them on the website, and it turned out everyone was using the other calculators and no one was using my percentage calculator anymore. It was an extremely valuable lesson: people want products tailored to their problems—the fewer the steps, the better. Basically, since then, we’ve been trying to create calculators for every possibility, and in 2026, here we are, with almost 3,700 calculators and counting.
You made the bold decision to keep Omni Calculator completely free. What challenges came with that choice, and how did it shape your growth strategy?
It was quite easy back then to position yourself at the top of Google Search, and the traffic provided ad income. Even if there were other options, like doing jobs for corporations to create tailored tools just for them, the vision of creating tools for anyone, anywhere—with a constant feedback loop of what to improve and the autonomy to do any project you want—meant I never even considered those other options.
Managing a business with millions of users requires balancing quality, scale, and speed. How do you ensure accuracy and trust across hundreds of calculators?
I love this question because it allows me to switch focus from me to my team, which is definitely what I’m most proud of when it comes to Omni. At the beginning, it was just me, but very early on I started hiring people, and eventually, we scaled to the small-to-medium-sized company that we are today. Our website runs great, looks great, and the numbers are coming out correct because we have experts on board—we have a great IT team, we have great marketing people, and, to answer your question, we have a great content team. The people who create our calculators are experts in their fields. We prioritize education, which is why most of our content creators have PhDs in their fields and why we can create extremely complicated calculators that work flawlessly.
Looking back, what leadership lessons stand out most from building a multi-million-dollar business without traditional growth tactics?
Focus and something I call action bias. You can sit, think, and plan, and then think about the plan, then change it, then think about what’s wrong with it, then plan again, and in the loop we go. I know it’s not groundbreaking or sexy, but you really have to put the hours in to get the results out—no theory can teach you as much as practice.
As Omni Calculator continues to grow, what is your long-term vision for the company and its impact on global access to knowledge?
The ultimate goal is to have tools that allow the user to calculate anything they want without any extra steps—come in with the inputs they have and come out with the answer as quickly and efficiently as possible. There’s really nothing more to it. We’ve been working towards this goal since the beginning of the company’s existence, and the goal has never changed.
