Summarum

Русский

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.

Install

Grab the latest Summarum_*_x64-setup.exe (or arm64-setup.exe on Windows on ARM) from Releases, run it, done. The whole app is about 2 MB. It checks for updates on its own after that.

Requirements:

• Windows 10 (1803+) or Windows 11, 64-bit.
• WebView2 Runtime — already part of Windows 11 and most updated Windows 10 systems; if it's missing, the installer downloads it automatically.
• Internet connection is only needed for live rates and market data — everything else works offline (rates fall back to a cached/bundled snapshot).

What it understands

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.

Handy things

• 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, .txt or .md file 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, or 2024-12-31). Settings is split into General / Format / Data / Updates tabs.

Extensions

Note: extensions run inside a WebAssembly sandbox — no file, network or app access, only the numi API 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.

Bugs and ideas

Open an issue. A line of text and what you expected is enough.

For developers

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 installer

To build from source you need:

• Node.js 22.6 or newer (npm run icons relies on Node's built-in TypeScript support)
• Rust (stable, MSVC toolchain)
• Visual Studio Build Tools with the "Desktop development with C++" workload (the MSVC linker)
• See the Tauri prerequisites page if anything refuses to compile

Stack: Tauri 2 + TypeScript + CodeMirror 6.

Credits

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.

License

PolyForm Noncommercial 1.0.0 — free for personal, educational, and other noncommercial use. Commercial use (including resale or repackaging) is not permitted.