Think freely. We’ll do the math.

Write calculations like notes. Answers appear beside every line.

  • macOS 26+ · Apple Silicon
  • Free & open source (MIT)
Download for macOSGitHubSee it in action
Numlex: a plain-text sheet of calculations with a live results column on the right

See it in action

Four real sheets, recorded in the app.

Variables & Functions

apple = 65, then sin(radians(30)) — name a value once and reuse it anywhere.

Variables & Functions: apple = 65, then sin(radians(30)) — name a value once and reuse it anywhere.

Natural Calculations

“June 12 + 45 days” answers Jul 27 on its own line — dates, headings and totals in plain text.

Natural Calculations: “June 12 + 45 days” answers Jul 27 on its own line — dates, headings and totals in plain text.

Units & Currencies

“250 km to m”, “34 C to F”, “$500 to EUR” — the converted value lands beside the line.

Units & Currencies: “250 km to m”, “34 C to F”, “$500 to EUR” — the converted value lands beside the line.

Linked Answers

The 43,5 answer becomes a live bubble: reuse it further down and it stays tied to its source.

Linked Answers: The 43,5 answer becomes a live bubble: reuse it further down and it stays tied to its source.

More than calculations

A sheet is a workspace you keep coming back to, not one-off scratch work.

  • Sheets you can organise

    Give each sheet a name, file it under a folder tab, and drag it elsewhere when the work moves — # Household is the heading you type to start one.

  • Rates and weather

    Ask for the current temperature in weather in Lisbon and only that place name is sent. Currency rates need no name at all: the rate table refreshes in the background, so the last good values keep working offline. Numlex reads no GPS either way.

  • Take the work with you

    Each sheet leaves as a plain .nlx file you can copy, keep and re-import; appearance, decimal places and interface language are native settings.

The full catalog — every function, unit and currency — lives in the documentation, with a feature list in the README.

Latest release

Numlex 4.9.6

Adds saved window placement, a compact workspace, more notebook controls, automatic local-unit conversion, expanded weather queries, and drag-to-export for sheets.

See what’s new Release on GitHub

Local-first, by design

Your sheets and every calculation run on your Mac. Three kinds of request can go online: a currency-rate refresh that runs in the background, weather and place lookups for a name you type, and app update checks — which also run automatically.

Stays on your Mac

  • Sheets, folders, variables and settings live in ~/Library/Application Support/Numlex.
  • Calculations, dates, unit conversions and the bundled catalogs all resolve offline.
  • No account, no sync, no GPS — and a sheet leaves as a plain .nlx file you own.

Can go online

  • Currency rates — a background refresh from open.er-api.com of a public rate table that carries nothing identifying; conversion lines can refresh it too, and the last good table keeps working offline.
  • Weather and places — Open-Meteo resolves the place you type (“weather in Lisbon”, “location of …”). Numlex reads no GPS and asks for no location permission: only that name is sent, and results are cached.
  • Update checks — the app reads its update feed on its own schedule or when you ask it to; the announced disk image is downloaded from GitHub only when you accept an update. Plain HTTPS requests with no identifiers.

Nothing else leaves your Mac. Sheet contents are never sent: no analytics, no telemetry, no crash reporting, no sync service.

Every request, in detail — the full allowlist, exactly what each one sends, and the offline fallbacks.

Download & install

Free and open source under the MIT license. Needs macOS 26 or later on Apple Silicon — there is no Intel build.

Download for macOS

4.9.6 · October 9, 2026 · release notes

Or with Homebrew

brew install --cask Qulierm/tap/numlex

From the custom Qulierm/homebrew-tap. The cask tracks stable releases; the newest version can take a little longer to appear there than on the download page above.

Install in three steps

  1. Open the downloaded disk image — a plain, unstyled disk image with Numlex.app and an Applications shortcut.
  2. Drag Numlex.app to Applications.
  3. Launch it from Applications (or Spotlight).

If macOS asks about “Numlex.app”

Numlex is signed ad-hoc and is not notarized, so a first launch may be blocked. Control-click (right-click) Numlex.app → Open → confirm (on newer macOS: Open Anyway in System Settings → Privacy & Security). Whether that works depends on your macOS version — Apple's guide: open an app from an unidentified developer — and please don't disable Gatekeeper system-wide.

Frequently asked questions

Why is there no Intel build?
Numlex is a native Apple Silicon app (arm64) for macOS 26 and later. No Intel build exists, so it won't run on Intel Macs.
Is Numlex free?
Yes — it's free and open source under the MIT license. No account, no subscription, no in-app purchases. The source is public on GitHub.
What goes online?
Three kinds of request can go online: a currency-rate refresh that runs in the background, weather and place lookups for the place you type, and app update checks. No GPS, no account, no sync, no analytics — sheet contents are never sent.
Can I move my sheets between Macs?
Yes — export a sheet as a .nlx file and import it on another Mac. App-wide constants and custom units are not embedded in exports, so bring those along separately; see the documentation.