FXPad

FXPad is a calculator and a currency converter in one. You type a sum in the currency you're working in, say 120 + 35 × 2 in US dollars, and every other currency on your list updates as you type.

What it does

• Live conversion: each keypress recalculates every currency on the list.
• A real calculator: brackets, percentages and exact decimal maths, so 0.1 + 0.2 is 0.3.
• Your list, your order: add any of the 166 currencies, remove the ones you don't need, drag to reorder. Tap a currency to make it the one you type in.
• Works offline: the app ships with a snapshot of exchange rates, so it works on the first launch without a connection, and keeps the last rates it downloaded.
• Copy a value: press and hold a currency to copy its amount.
• No account, no ads, no tracking: your list stays on your device.

Where it runs

One React codebase, shipped five ways:

• Web: an installable web app that works offline, at crkayes.com/fxpad
• macOS and Windows: a Tauri 2 desktop app
• iOS and Android: a Capacitor 8 mobile app

FXPad is still being built. The web version is live, so you can use it now. The other versions aren't in the app stores yet, and their download links will appear on this page when they are.

Exchange rates

The apps never call a rate provider directly. A small Cloudflare Worker fetches rates every hour, checks them, and serves one file the apps download. If a major currency jumps more than 10% in an hour, the worker rejects the update and keeps the last good rates.

The worker isn't switched on yet. Until it is, the web version downloads rates straight from Exchange Rate API, which updates them once a day.

What's next

Ideas on the list: crypto and gold, calculation history, rate charts, tip and split-bill tools, VAT and discount helpers, home-screen widgets, rate alerts, more languages, and a mini version for the Mac menu bar and Windows tray.