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npm Bundle Size Lookup

Look up an npm package's **minified / gzip size**, **dependency count** and **tree-shake** (sideEffects) flag. Stack multiple packages to compare side-by-side (green bar tracks gzip size). The go-to check when picking a dep. Powered by bundlephobia.com's public API.

Popular packages
Enter a package or pick a popular one below.
β€ΊHow to use
  1. Type an npm package name (react, lodash, @vercel/analytics); pin a version with react@19.2.4 if needed.
  2. Hit Query or click a Popular chip. Successive lookups stack so you can compare side-by-side.
  3. Each card shows: Min (minified), Gzip (actual transferred bytes, green), Deps (transitive deps count), Side effects (tree-shakeable shows green).
  4. The green bar shows gzip size relative to the largest in the list β€” useful for spotting the bulky one at a glance.
  5. Click the package name to open bundlephobia.com for the full breakdown; βœ• removes a row.
Tips
  • Gzip is what users actually download (typically 60-80% smaller than min). lodash ships 25KB gzip altogether, but lodash-es tree-shakes down to only the functions you import.
  • Side effects = false means the bundler can drop unused exports. react, lodash are 'yes'.
  • date-fns vs dayjs vs moment is the classic case study: moment is ~200KB gzip (avoid), dayjs is 2KB, date-fns is ~12KB but tree-shakes.
  • Watch the deps count: more transitive deps = longer lockfile, slower CI installs, more CVE surface.
  • vs bundlephobia.com: that's the source. We make multi-package side-by-side easier β€” handy in dep evaluation meetings.

πŸ’‘ This tool fetches bundlephobia.com's public API (not local). The package name is sent there, but for public npm package names that's not sensitive.

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