About
Ratio is a notepad calculator that answers as you type. Write a line like "dinner 84 eur / 3" and the result appears beside it. It handles currencies (160+, including major cryptocurrencies) with rates that refresh automatically, over 150 units, and dates and time zones, and it shows its working so you can see how each answer was reached. Lines can reference earlier results, so changing one value updates everything below it.
Beyond everyday conversions, Ratio supports lists, plots, live countdowns, and loan or salary calculations, and it can be used from the menu bar, a notch-style pop-up, the Terminal, or as a Claude integration via MCP. Ratio runs on Mac, Windows, and Linux, and works offline. All calculations happen on your computer, and nothing you type is sent anywhere.
Ratio is available as a 7-day free trial with no account or card required. After the trial, it is a one-time purchase, with options for one, two, or three computers and a 14-day refund policy.