Show HN: I built a tool to show how much ARR you lose to FX fees

I started my career as a finance manager, transitioned into product management, and now I’m building my own products.

Back in my finance days, while managing a £6M budget, I uncovered a £15k leak hiding in plain sight: FX fees.

Today, I see solo founders making the exact same mistake. I realised most founders are quietly losing 2-5% of their revenue to what I call the Lazy Tax: - Stripe's ~2% auto-conversion fee on inbound revenue, - plus their local bank's ~3% spread when paying for global SaaS tools (AWS, Claude, Ads).

So I built FixMyFX to show founders their exact leak and how to fix it (using multi-currency accounts to achieve a zero FX leak setup).

Initially, I had Claude build this in React. Realised a simple calculator shouldn't need a 150kb payload and a complex build process. Threw the React code away and rebuilt it as a single lightweight HTML file using Alpine.js and Tailwind.

It's completely free and ungated. I hope it helps you keep a bit more of your hard-earned revenue. Would love your feedback.

Tania