omacusUnits
Distance, time, temperature, data, cooking, area and hundreds more, converted with in or to.
3.5 km in miles2.17 miles
2 cups in ml473.18 ml
v1.0.9Free & open source · Omarchy, Linux, macOS, Windows
Math, the way you write it.
Omacus is a notepad calculator. Jot down prices, units, currencies and time zones in plain words, and the answers line up beside them as you type.
$
curl -fsSL https://omacus.com/install | bashOn Omarchy it offers a keybind and a floating window.deb, .rpm, .tar.gz
$
curl -fsSL https://omacus.com/install | bashInstalls Omacus.app, no security promptor download the .dmg
Installs in a click, no admin needed · Windows 10 and 11or one line in PowerShell
A replay with real answers from the Omacus engine.
// the one-minute tour
See it in a minute.
// what it understands
Write it like you'd say it.
No formula syntax to learn. Omacus reads the way you already write notes, and quietly ignores the words that aren't math.
Unit conversion guide
Currencies
160+ currencies with live exchange rates, cached so it keeps working offline. Symbols or codes, your call.
$30 in EUR26.69 EUR
£250 in USD$332.96
Time zones
Abbreviations, cities and countries, with daylight saving handled. Tells you when it lands on another day.
6pm PST in Tokyo10:00 AM JST (next day)
9am EST in London2:00 PM BST
Percentages
The everyday phrasings: of, on, off, as a percent of, and what a number is a percentage of.
15% off $1,299$1,104.15
$120 as % of $48025%
Variables & totals
Name things once, reuse them below. total, average and prev work over each block.
rate = $85/hour$85 / hour
rate * 30 hours$2,550
Notes, not code
Headers, comments, labels and plain prose sit right next to the math. Lines read like a notebook.
Lunch with Sam $18$18
Rent: $1,450$1,450
Days & dates
Count to or from any date in days, weeks, months or workdays, or add time to today. Christmas and New Year's work by name.
days from Dec 20 to Jan 516 days
workdays in Nov 202621 workdays
For developers
Download times, CSS units and colours, with a swatch beside each colour. Hex, binary and the command line too.
4 GB at 100 Mbps5 min 20 s
#ff8800 in hslhsl(32, 100%, 50%)
Share as a link
One link opens any page live in a browser, or straight in Omacus. The page travels inside the link; nothing is uploaded.
How sharing works
// in your browser
Nothing to install. Anywhere.
The same engine runs at app.omacus.com, on any computer or phone. Every answer matches the desktop app, because it's the same code.
- Add it to your Home Screen and it opens like an app, offline.
- Share any page as a link; it opens live, or straight in the desktop app.
- Export and import plain .txt pages, the desktop app's own format.
// pages
Nothing to save. Ever.
Keep a page per trip, budget or invoice. Like Sublime Text, every keystroke is saved, and closing the window loses nothing. A fresh library opens with an Examples folder: Trip Budget, Groceries, and a monthly budget that reads @trip.total.
- Reopens exactly where you left off, cursor included.
- Folders, two levels deep, and a password lock on a page or a folder.
- Plain text files on disk, so you can search them or back them up.
- Deleted pages go to the trash, and can be restored.
// themes
Looks like the rest of your desktop.
On Omarchy, Omacus wears your theme and switches the moment you do. Elsewhere it follows your system's light or dark mode, or any colors you give it.
// keyboard first
Hands stay on the keys.
Everything has a shortcut, and F1 opens a built-in guide where every example is calculated live.
New page Ctrl N
Find a page Ctrl J
Jump to page Ctrl 1–9
Copy last result Ctrl Shift C
Accept suggestion Tab
Collapse sidebar Ctrl B
// command line
Also lives in your terminal.
The same engine answers one-off questions, or evaluates a whole page from a pipe. Handy in scripts, launchers and status bars.
$ omacus '$100 in EUR' 89.17 EUR $ omacus '6pm PST in Tokyo' 10:00 AM JST (next day) $ printf 'rent = $1450\nrent * 12\n' | omacus - $1,450 $17,400
// private by design
Your pages stay yours.
No tracking in the app. Pages stay on your device until you turn on sync. A sealed copy can then be stored, and the server cannot read it.
On your computer
Pages are plain text files in a folder on your disk. Search them, back them up; they're yours.
In your browser
The web app saves pages in that browser. Turn on sync to open them on your other phones and computers. The server stores a sealed copy and cannot read it.
In a share link
The page rides after the #, the part of a link browsers never send to a server. Only people you give it to can read it.
The only things Omacus fetches are exchange rates, and on the desktop, a check for new versions. Neither carries anything you've written. All of it, in plain words
Your pages, on every device you link.
Turn on sync in the web app. Pages are encrypted on your device before they leave. The server cannot read them. Twelve recovery words are the way back in. A sealed copy is saved each night.
// questions
Good questions.
What is Omacus?
Omacus is a free, open-source notepad calculator for Linux, macOS and Windows. You write calculations in plain words, one per line, and each answer appears beside its line as you type. It understands units, currencies, time zones, percentages, variables and running totals, and it was made first for Omarchy.
Is Omacus free?
Yes. Omacus is free and open source under the MIT license. The notepad needs no sign-up, no email, no password, no ads and no tracking. Sync is invite-only. This website only counts visits, with Cloudflare's cookieless analytics.
Which systems does it run on?
Omarchy and any 64-bit x86 Linux (as a .deb, .rpm, tarball or one-line installer), macOS on Apple Silicon and Intel, and 64-bit Windows.
How do I convert time zones?
Type the time and both zones, like 6pm PST in Tokyo. Omacus answers 10:00 AM JST (next day). It knows abbreviations, cities and countries, and adjusts for daylight saving.
Does it work offline?
Yes. Everything is calculated on your computer. The internet is only used to refresh exchange rates and to check for a new version (on launch and every few hours), and the last rates are cached so currency math keeps working offline.
How is it different from a regular calculator?
A regular calculator shows one number at a time. Omacus keeps a whole page: every line keeps its answer, you can add notes beside the math, name values and reuse them, and changing a line updates everything below it. Pages are saved as you type.
Can I use it from the terminal?
Yes. omacus '$100 in EUR' prints the answer, and omacus - evaluates a whole page from standard input, one result per line.
Where are my pages stored?
On the desktop, as plain text files on your own disk. In the web app, in that browser until you turn on sync. The sealed copy is described on Sync. The server cannot read it.
More in the guides and docs, real pages in use cases, or ask on GitHub.
// download
Your next calculation is a sentence.
Free and MIT licensed, for Omarchy, Linux, macOS and Windows. One command installs it, and it keeps itself up to date.
$
curl -fsSL https://omacus.com/install | bash
or try it first
Open the web appRuns in your browser. Nothing to install.