Calipers

Installation

Calipers is available as a Chrome extension from the Web Store, or you can build it from source for Chrome and Firefox.

Chrome Web Store

  1. Visit the Calipers listing on the Chrome Web Store.
  2. Click Add to Chrome.
  3. Confirm the permissions prompt.
  4. Activate Calipers with Cmd+Shift+M (Mac) or Ctrl+Shift+M (Windows/Linux), or click the extension icon in your toolbar.

Build from source

git clone https://github.com/heysolomon/calipers.git
cd calipers
pnpm install
pnpm build --filter=@calipers/extension

Then load the extension in your browser:

  1. Open chrome://extensions (Chrome) or about:debugging (Firefox).
  2. Enable Developer mode (Chrome) or click This Firefox (Firefox).
  3. Click Load unpacked and select apps/extension/dist/.

For Firefox, use the dedicated build:

pnpm build --filter=@calipers/extension -- --config vite.config.firefox.ts

Browser support

BrowserStatusNotes
ChromeSupportedManifest V3
FirefoxSupportedManifest V2 build
EdgeSupportedUses Chrome Web Store build
SafariNot supportedNo extension API

Permissions

Calipers requests only what it needs:

  • activeTab — inject the overlay on the page you are viewing
  • scripting — run measurement tools when you activate Calipers
  • storage — save guides and preferences locally
  • tabs — capture screenshots when you press S

No data is collected or transmitted. See the privacy policy for details.