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Oktan: The Car Expense Tracker I Built 15 Years Ago

Oktan

Over fifteen years ago, I created Oktan, a desktop application designed to track car expenses, fuel consumption, and service maintenance logs. This wasn’t just another project—it was my way of bringing structure to something I deeply cared about: understanding and managing expenses in a digital format.

Oktan screenshot

At the time, smartphones were just emerging, but I didn’t own one. That’s why I built Oktan as a desktop application using C++ and the Qt framework, with SQLite as the database. It started as a personal tool but later became publicly available, even earning a mention in Serbia’s leading computer magazine.

The Problem Oktan Solved #

Owning a car comes with many hidden costs—fuel, maintenance, insurance, repairs—and I wanted to track them all. The goal was simple:

  • Log every fuel refill and service cost.
  • Get insights into how much the car was actually costing.
  • Make better decisions when it was time to upgrade or replace the vehicle.

Back then, there weren’t many apps available for this purpose, and certainly not as easily accessible as today’s mobile apps.

Development & Challenges #

I developed Oktan in my free time over several months, handling all the coding myself while hiring a designer for marketing graphics. The hardest part wasn’t writing the code—it was pushing through to actually release the app. Finishing a project and making it available to users is a challenge many developers face, and Oktan taught me the importance of persistence.

Features & Functionality #

Oktan included:
✅ Fuel consumption tracking
✅ Service and maintenance logs
✅ Graphical reports to visualize spending

The Outcome #

Though I didn’t track user numbers, those who used Oktan gave me positive feedback. However, I quickly realized a major issue:
💡 People are more interested in knowing where they can save money rather than tracking where they already spent it.

A budgeting-focused app would have likely gained more traction than an expense-tracking tool.

Lessons Learned #

Building Oktan was an invaluable experience that helped me:

  • Learn how to ship a complete product from idea to release.
  • Understand how to create Windows installers and package Qt apps with all necessary dependencies.
  • Gain experience with data visualization and charting in Qt.
  • Develop a structured approach to app architecture, which I later reused in projects like Silos.

Would I Rebuild Oktan Today? #

Short answer: No.
Long answer: The market is now flooded with similar apps, and the business potential for such a project is minimal. If I were to rebuild it, I’d choose a mobile-first approach using Flutter, ensuring it runs on both Android and iOS.

Oktan may not be relevant today, but it was a crucial stepping stone in my journey as a developer. It reinforced the importance of finishing projects, understanding user behavior, and choosing the right platform for the problem at hand.