CertusFX Currency Converter FX

NestCalc.ai LLC

In-app purchases

About this app

CertusFX turns currency data into decisions.

Convert between 30 major currencies using the European Central Bank's official daily reference rates — free, no account, no sign-up. Every screen names its source and tells you how old the data is, so you always know what you're looking at.

These are official once-a-day reference values, not live dealing quotes. If you need tick-by-tick dealing prices, this isn't that app — and it says so rather than implying otherwise.

Free, always:
Convert 30 major currencies at ECB reference rates. Chart any pair of those 30 currencies over 7 days, 1 month, 1 year, 5 years, or the full history back to 1999 — the charts are not limited by plan. Track 3 pairs on a watchlist and set 1 rate alert.

CertusFX Pro adds:
160 currencies instead of 30. Government bond yield curves for the US across 11 tenors, plus 10-year series for other major economies. An AI trend outlook for every major pair, refreshed daily. An unlimited watchlist and unlimited alerts. Compare two pairs on one chart, and export a pair's history to CSV.

Pro is a pass, not a subscription.
One payment, nothing auto-renews, nothing to cancel. Buy another pass whenever you want and the time stacks onto what you have left. No trial that quietly bills you, no card on file waiting for a renewal date.

Rate alerts run on your device. No push server, no account required, no tracking of what you watch.

CertusFX is available on iPhone, Android, and the web.

What’s new

Buying a pass is now more dependable. If your payment takes a while to clear, Pro turns on by itself as soon as it does. Right after you buy, Pro stays on while the store confirms your purchase. A pass you bought before signing in now moves to your account when you sign in. Plus stability improvements that help us fix problems faster.