Why I built this
Most free online calculators show math as flat text — 3/4 in one line, no real fraction rendering. That never felt right, especially compared to an actual physical calculator.
So I built OnlineScientificCalc — a free scientific calculator with a proper natural display. Fractions, integrals, derivatives all render the way they would on a real calculator screen.
Tech stack
Built with Astro.js + Tailwind CSS v4. Modeled after the Casio fx-991 layout (same buttons, SHIFT/ALPHA system) so it feels familiar if you've used one before.
Try it
🔗 https://onlinescientificcalc.com — no signup, no download, works instantly. Also just launched this on Product Hunt today if you'd like to check it out there -> https://www.producthunt.com/products/onlinescientificcalc
Would love feedback from this community — especially on performance, UX, or anything that feels off. This is my first shipped project and I'm planning to build more tools like this.
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