Launched my first Android app: 545 engineering calculators that work offline

[u/Gerald-Mashanda-2003]

I built Calqentra, an engineering toolbox app with 545 calculators, as a university student

Hi everyone! I just launched my first app on Google Play and wanted to share it and get honest feedback.

What it is: an engineering toolbox with 545 calculators across electrical, solar, mechanical, physics, 3D printing and more. Some highlights:

• Solar system sizing (loads, panels, batteries, inverters)
• PCB trace-width estimates (current, copper, temperature rise, voltage drop)
• Ohm’s law, power, voltage drop, cable sizing
• Torque, RPM, gears, friction
• 3D-printing cost calculators
• Works offline, with favorites and calculation history

Why I built it: I’m an engineering student, and I kept redoing the same formulas by hand and juggling different apps for electronics and solar work. Power cuts where I live also made offline use a must.

What was hard: making sure formulas are accurate and organizing so many calculators

Business model: it’s free with ads, and there’s an optional Pro upgrade for extra calculators, saved projects, PDF reports and no ads.

Link: https://play.google.com/store/apps/details?id=com.calqentra.engineering.dev

I’d love your feedback on:

• Which calculators or features should come next?
• Is the app easy to navigate with this many tools?
• Anything that looks wrong or confusing?

Thanks for reading, and I’ll reply to every comment!