Hey HN! Maker here.

        I built APYCalc.net after getting frustrated with financial calculators that require email sign-ups and track your inputs.
        
        **Tech Stack**:
        • Vanilla JavaScript (no frameworks, no dependencies)
        • 100% client-side execution (calculations never hit a server)
        • No cookies, no analytics, no tracking
        • Hosted on Cloudflare Pages
        
        **How It Works**:
        All calculations use industry-standard formulas (e.g., APY = (1 + r/n)^n - 1). Your inputs are processed entirely in-browser via Web APIs.
        >
        **Why I Built This**:
        I compared 10 popular APY calculators with identical inputs. Results ranged from $61,350 to $62,780 on $50K over 5 years. Also, 8/10 sent data to servers.
        
        **Next Steps**:
        Considering open-sourcing if there's interest. Also thinking about adding tax-adjusted return calculators.
        
        Feedback welcome! Especially from folks who've thought about privacy in fintech tools.