Hi Product Hunt 👋 I'm Sujit, and I built UToolios as a solo project. The idea is simple: most "free online calculator" and dev-tool sites either want an account, bury the tool under pop-ups, or quietly send what you type to their server. I wanted the opposite — tools that just work, instantly, and keep your data on your device. Everything runs in your browser. Your mortgage numbers, your weight, the JWT you paste — none of it is uploaded. You can open DevTools → Network and check. A few things I cared about: • Real answers, not just a number — every tool explains its formula and where it breaks down (e.g. why BMI misreads athletes). • Units people actually use — the BMI calculator does kg + feet/inches, because that's what most people outside the US search for. • Tested — every tool ships with automated correctness tests. • Embeddable — bloggers can drop any calculator into their own site for free. I wanted every tool that we search online to come to one place. It's early: 16 tools today, with more on the way. What tool should I build next? I read every comment.

UToolios

Free calculators & dev tools that never see your data

Free calculators & dev tools that never see your data