Ratio

Under review

Type a sum, get the answer as you write

Notepad calculator that answers currency, unit, date and time zone questions as you type, for people who do quick money and everyday math on Mac, Windows or Linux.

Built by Adrian Viziteu · Productivity · SaaS · Notes · Paid

Coming soon on Launch Llama Tools

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Adrian Viziteu (Joined Nov 2026)

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Notepad calculator that answers currency, unit, date and time zone questions as you type, for people who do quick money and everyday math on Mac, Windows or Linux.

Ratio demo video

About

Ratio is a notepad that calculates as you type. Write a line like "rent 1,200 + bills 180" or "3pm in Tokyo" and the answer appears beside it. It handles 160+ currencies with live rates, crypto, 150+ units, dates and time zones. Change one number and every line below updates. Split bills by name, work out salary or loans, and solve equations. Everything runs on your computer, works offline, and you buy it once for Mac, Windows or Linux.

Competitors: Numi, Soulver, Calca, Parsify, Numara, Raycast, NoteCalc, Qalculate, SpeedCrunch

Follow Ratio: X (Twitter)

Key Features

Calculates currencies, crypto, units, dates and time zones on each line
Refers to earlier lines by number so one change updates everything below
Splits bills by name with @names and shows who owes what
Opens a calculator from the notch and pins lines to the menu bar
Runs every calculation locally and works offline
Shares a whole sheet as a link that opens in any browser

Use Cases

Splitting a restaurant bill between friends and sending the amounts to the group chat
Checking a foreign currency quote or converting a trip budget between euros, dollars and pounds
Working out take-home pay, mortgage or loan figures in a running notepad without a spreadsheet

From the founder

Who it's for

“People who do quick math all day, like freelancers checking quotes, friends splitting a bill, travellers converting currencies, or developers working out subnets. Before Ratio they juggle a calculator, a spreadsheet and a currency site, and lose track of how they got each number.”

Why I built it

“'m Adrian, and I kept doing everyday sums in a notes app and then retyping them into a calculator. I wanted one place where I could write things down the way I'd say them, like "dinner 96 eur / 3 in usd", and see the answer right away, with every step kept. So I built Ratio: private, offline, and yours to buy once.”

— Adrian Viziteu, founder of Ratio

Who it is for

Students or teachers, who get half price with a school email
Mac, Windows or Linux users who want quick calculations without opening a spreadsheet
Developers who need quick subnet, hash or cloud bill calculations

Pricing

19.99

FAQ

What is Ratio?

Ratio is a notepad calculator for Mac, Windows and Linux. You type calculations as plain text, like "dinner 84 eur / 3", and the answer appears beside each line as you type. It understands currencies, crypto, units, dates and time zones.

Does Ratio run on Windows and Linux?

Yes. Ratio runs on Windows 10 and 11 (64-bit) and on 64-bit Linux (Ubuntu 22.04 or newer, Debian, Fedora and others, as an AppImage or a .deb). It uses the same engine as on the Mac, so every line gives the same answer. The trial and the license work the same way everywhere, and a 2- or 3-computer license can mix a Mac, a PC and a Linux machine. iCloud sync, Liquid Glass and the Terminal command are Mac only for now.

Can Claude or other AI assistants use Ratio?

Yes, on the Mac. Ratio comes with an MCP server, so Claude, Cursor and VS Code can work out currencies, stock prices, units, dates and VAT with Ratio instead of guessing. Setup: https://useratio.app/calculator-mcp-server

Does Ratio work offline?

Yes. Every calculation happens on your computer. Exchange rates need a connection to refresh, and while you're offline, Ratio uses the last rates it downloaded.

Do I really pay only once?

Yes. You pay once, and that's it. Updates are included.

Is there a free trial?

Yes. Ratio is free for 7 days, with no account and no card. If you buy it and it isn't for you, email us within 14 days and we'll refund it.

How do I move my license to another computer?

In the app, open Ratio Pro and click “Deactivate this Mac” (or “Deactivate this PC” on Windows and Linux). Then enter the same key on the new computer, whether it's a Mac, a PC or a Linux machine.