Babbage

A sheet

A sheet is a list of lines. Names you define turn green, amounts pick up their own colors, and the answers sit in a column on the right.

What it does

Everything here works today.

• Plain-language lines

  Write what you mean: 150 lb in kg, 3 hours 20 minutes in seconds, 12 plus 3. Words around a calculation are ignored, so a line can read like a note.

• Exact until it can’t be

  Fractions stay fractions, so 1/3 + 1/6 is exactly one half. When an answer has to be rounded or approximated it is marked with a small ≈, and a power too big to hold exactly is approximated and marked, never silently.

• Percentages

  20% of 85, 5% on $40, 180 is 10% off what, 50 to 75 is what %, and percentages that multiply and divide each other.

• Units and conversions

  Over two hundred units with exact conversion factors: lengths, weights, volumes, speeds, energy, data, temperatures, fuel economy (8 L/100km in mpg), and compound units such as km/h.

• Money

  Currency symbols and codes, your region’s dollar, a sales tax or VAT setting, and exchange rates you type in yourself. Babbage fetches no rates: a rate you don’t give it is a question, not a guess.

• Variables and line references

  rent = $900 and use rent below it, or refer to an earlier answer with line3. Names are colored, hovering shows their value, and Esc or Tab finishes a name.

• Totals, subtotals and tags

  A Total chip adds the sheet up as you go and says which lines it left out. Subtotal lines, #tags and total of #food add up part of a sheet.

• Dates, times and time zones

  June 3 + 3 weeks, days until Christmas, 9am London in Tokyo, workdays (list your holidays and they are skipped), timestamps, ISO 8601, lap times and video timecode.

• Finance

  Compound interest, present value, loans and returns, written the way you would say them.

• Functions

  Roots, logarithms, trigonometry in degrees or radians, rounding, averages and medians, gcd and lcm, conditionals, and numbers in any base with bitwise operators.

• Control over each answer

  The … beside an answer sets its decimal places, thousands separators, k/M notation or fixed money digits for that line alone. Hold Alt and drag a number to count it up or down.

• Settings that matter

  Number format, currency, tax, the working day and holidays, the update check, colors, fonts, text and heading size. Everything saves to a plain settings file.

• Light and dark

  On Omarchy, Babbage follows the current theme, light or dark, live, and keeps every color readable on whatever the theme provides. Elsewhere it follows the system’s setting.

• A quick calculation from anywhere

  babbage --quick opens a small floating window for one sum, or brings the open window forward on Hyprland. On Omarchy, babbage setup omarchy adds a key and a menu entry in files of its own, with backups, and --remove takes them out again.

• From the terminal

  bbg answers a line, a sheet file or a pipe, prints JSON on request, and completes options and your sheet names with Tab in bash, zsh and fish.

• Export

  Send a sheet out as text, CSV, HTML or PDF with Ctrl+Shift+E.

Installed in one line

The installer downloads the latest release and checks every file against its published SHA-256 before anything is installed. The program goes under ~/.local, with two commands beside it: babbage opens the window, and bbg answers from the command line. It also adds a launcher entry with an icon and tab completion for bbg. No root needed.

$ curl -fsSL https://github.com/jrimmer/babbage/releases/latest/download/install.sh | bash

# then, from anywhere
$ bbg 20% of 85                  # 17
$ bbg 150 lb in kg              # 68.0388555 kg
$ bbg budget.bbg                # a sheet file: every line answered
$ echo "3 * \$4.50" | bbg       # standard input is a sheet too

Run the same line again to update. Add --uninstall after bash -s -- to remove it. Prefer to download by hand? The release page has the AppImage and a tarball, each with a .sha256 file; check one with sha256sum -c and run it. To build from source, clone the repository and run cargo build --release.

Your sheets are text files

Each sheet is one plain .bbg file in your data folder (~/.local/share/babbage by default), saved as you type. Open it in any editor, back it up with the tools you already use, or move it with mv.

# a sheet is the lines you typed
$ cat ~/.local/share/babbage/Weekend\ trip.bbg
# Weekend trip
flights = $412 × 2
hotel = 3 × $138
…

A line’s own formatting from the … menu is kept at the end of the file and follows the line’s text, so editing a sheet elsewhere does not scramble it.

Updates, and what leaves your computer

Babbage works offline, and the only thing it can do online is look for a newer version of itself. When it starts, at most once a week, it asks the release page for its list of releases. That request carries your IP address and nothing from your sheets or settings. If a newer version exists, an Update pill appears with the release notes and Install, Later and Skip buttons; nothing is downloaded until you press Install, and the file is checked against its published SHA-256 first.

Choose Off, Monthly, Weekly or Daily in Settings, or set BABBAGE_UPDATES=off and Babbage never goes online. The full list of what it asks, sends and keeps is in docs/updates.md.

The engine, as a Rust crate

The calculation engine is a separate crate, babbage-core, with no interface of its own. Hand it a line and it hands back an exact value and how to show it.

$ cargo add babbage-core

// in your program
use babbage_core::{evaluate, format_value, FormatOptions};

let value = evaluate("20% of 85")?;
let shown = format_value(&value, &FormatOptions::default());
assert_eq!(shown.text, "17");

The developer guide covers values, formatting, sheets, settings and what 1.x promises.

Read more

• User guide Fourteen chapters with screenshots, from your first line to every setting
• Developer guide Use the calculation engine in your own Rust program, with code samples that are run by the tests