A calculator that works like a notepad. Type what you're thinking — every line gets a live answer in the right column. No buttons, no formula syntax, just text.
# Trip to Lisbon
flights $420
hotel $95 * 4 nights
food 30€ a day * 4 days and museums 25€
total → $1,066.97
5 inches in cm → 12.7 cm
100 km/h in mph → 62.14 mph
$2000 in rubles → 144,060 ₽
20% off 1500 → 1,200
today + 6 weeks → 22 July 2026
1000 USD in EUR on 2024-01-01 → € 917.30
? * 1.2 = 1000 → 833.33
AAPL in USD → $213.55
days until 2027-01-01 → 183 day
chart → ▂▄▇█▆
Works in English and Russian at the same time: 5 метров в см, 20$ в евро,
сумма — no language switching.
Grab the build for your system from Releases. The whole app is about 2 MB and checks for updates on its own after that.
- Windows —
Summarum_*_x64-setup.exe(orarm64-setup.exeon Windows on ARM). Run it, done. - Linux —
.AppImage(chmod +x, then run) or the.deb/.rpmif you'd rather install it properly. Self-updating only works on the AppImage; deb and rpm are updated by downloading the next one. - macOS —
.dmg, Apple Silicon or Intel. These builds are not signed with an Apple Developer certificate, so the first launch has to be a right-click → Open rather than a double-click (or runxattr -cr /Applications/Summarum.apponce in a terminal). Every launch after that is normal.
Requirements:
- Windows 10 (1803+) or Windows 11, 64-bit, plus the WebView2 Runtime — already part of Windows 11 and most updated Windows 10 systems; if it's missing, the installer downloads it automatically.
- Linux with
webkit2gtk-4.1(Ubuntu 22.04+, Debian 12+, Fedora 36+) andlibayatana-appindicator3for the tray icon. - macOS 10.13 or newer.
- Internet connection is only needed for live rates and market data — everything else works offline (rates fall back to a cached/bundled snapshot).
Plain math — 2 + 2, 8 / (45 - 20%), parentheses, ^, sqrt, sin,
factorials, random(), random(1; 6). Decimal-exact: 0.1 + 0.2 is 0.3,
not 0.30000000000000004.
Words as operators — 12 plus 4, 20 divided by 4, 5 и 3. Text around
the math is ignored, so spent 20 on pizza and 5 on coffee just gives 25.
Units — length, weight, volume, area, temperature, time, angles, data
(1 GiB in MB), CSS px/em, speed, pressure, energy, power, frequency, fuel:
6 feet in meters 1 atm in mmHg 8 л/100км in mpg
2 hours 30 min in min 150 hp in kW 32 px in em
Money — ~150 currencies and the top-20 crypto with live rates
(refreshed hourly, cached for offline). $100 + 20%, 5 eth in USD,
9800 рублей в долларах.
Live market data — stock and commodity prices refreshed every 15 minutes:
100 AAPL in USD, 2 GC=F in USD (gold futures), MSFT + GOOGL.
Historical exchange rates — 1000 USD in EUR on 2024-01-01 looks up the
ECB rate for that exact date (via frankfurter.dev) and caches it permanently.
Percents the human way — 20% of 80, 20% off 1500, 5 as a % of 25,
20% of what is 30.
Dates and time — today + 2 weeks, tomorrow - today, time in New York
(also works with a raw IANA id: time in Europe/Berlin), now in unix,
1750000000 as date. Date literals: ISO (2024-01-01 + 30 days), or
dot/slash with a 4-digit year — 31.12.2024, 12/31/2024 — where the
day/month order for ambiguous cases follows the Date format setting.
days until 2027-01-01, days since 2020-03-15.
Goal seek — put ? where the unknown is and an = with the target:
? * 1.2 = 1000 → 833.33, 100 - ? = 30 → 70. Works for any expression
solvable by linear probe or bisection.
Programmer stuff — 0xFF & 0x0F, 1 << 4, 255 in hex, in binary,
plus in fraction (0.75 → 3/4) and in roman (2026 → MMXXVI).
Sheets that calculate — variables (rent = $500), running totals
(sum, avg, prev, count, min, max, product), # headers,
// comments. The status bar always shows the sheet total; select a few lines
to see just their sum. Add chart at the end of a block to draw a sparkline.
Cross-sheet references — pull a value from another sheet with @:
@Budget.total, @Budget.rent, @[Trip to Lisbon].food. A sheet made of
nothing but references becomes a live dashboard:
@Assets.total - @Debts.total. Give the source sheet a fixed name (not an
auto-derived one) so the reference doesn't break when its first line changes.
- Ctrl+Alt+N (configurable — the settings field records keys you press) shows/hides the window from anywhere. Closing hides to tray.
- Ctrl+W closes the current sheet (asks first if it has content).
- Ctrl+F (or the 🔍 button) searches every sheet at once — by text or by
result value:
>1000,<50,=100,~100(±1%). Click a hit to jump there. - Click a result to copy it. Copying a line copies it with the answer
(
rent * 3 = $1,500). Ctrl+Shift+C copies the whole sheet with answers. - Export as image — the ⤓ menu includes "Copy as image": renders the sheet to a PNG and puts it on the clipboard (falls back to file save if the browser blocks clipboard write).
- Drag the divider to resize the results column.
- Drop a
.numi,.sum,.txtor.mdfile into the window to open it as a sheet. - Pin and reorder sheets — click the pin icon on any sheet in the sidebar to keep it at the top; use ↑↓ to rearrange.
- Backups are automatic: a daily snapshot of all sheets (last 14 kept), and deleted sheets sit in a bin for 14 days (configurable) — restore one by dragging the file back in. Settings → Backups opens the folder.
- Data folder is configurable — point it at OneDrive/Dropbox and your sheets follow you between machines.
- Always on top (Settings) pins the window above everything else.
- The app checks for updates on launch and every few hours after that, and offers to install them — no manual download-and-reinstall. Settings → Updates → "Check for updates" runs one on demand, or turn automatic checking off entirely with the toggle next to it.
- Light/dark theme, en/ru interface, configurable precision, separators, and
date format (system locale,
31.12.2024,12/31/2024, or2024-12-31). Settings is split into General / Format / Data / Updates tabs.
Note: extensions run inside a WebAssembly sandbox — no file, network or app access, only the
numiAPI below. A script that hangs is cut off; a script that fails is skipped.
Drop a .js file into the extensions folder (Settings → Extensions folder)
and restart. The API is compatible with Numi extensions:
numi.setVariable("vat", { double: 20 });
numi.addUnit({ id: "floor", phrases: "floor,floors", baseUnitId: "meter",
format: "fl", ratio: 3 });
numi.addFunction({ id: "hyp", phrases: "hyp" },
(v) => ({ double: Math.hypot(v[0].double, v[1].double) }));Then 5 floors in meters → 15 m and hyp(3; 4) → 5.
Open an issue. A line of text and what you expected is enough.
Engine internals, project layout and how to add units/currencies: see ARCHITECTURE.md.
npm install
npm test # engine tests (259 cases)
npm run tauri dev # run the app
npm run tauri build # build the installerTo build from source you need:
- Node.js 22.6 or newer (
npm run iconsrelies on Node's built-in TypeScript support) - Rust, stable
- On Windows: the MSVC toolchain plus Visual Studio Build Tools with the "Desktop development with C++" workload (the MSVC linker)
- On Linux:
libwebkit2gtk-4.1-dev,libayatana-appindicator3-dev,librsvg2-dev,libxdo-dev,libssl-dev,patchelfand a C toolchain - On macOS: Xcode Command Line Tools
- See the Tauri prerequisites page if anything refuses to compile
npm run tauri build produces whatever the host platform bundles — NSIS on
Windows, deb/rpm/AppImage on Linux, .app/.dmg on macOS. Cross-compiling
between the three is not supported; the release workflow builds each on its
own runner.
Stack: Tauri 2 + TypeScript + CodeMirror 6.
Inspired by the excellent Numi by Dmitry Nikolaev — if you're on macOS, buy it. Summarum is an independent project, built from scratch for Windows, Linux and macOS.
PolyForm Noncommercial 1.0.0 — free for personal, educational, and other noncommercial use. Commercial use (including resale or repackaging) is not permitted.