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npm Package Size

Check bundle sizes of npm packages: minified + gzip, compare two packages.

Fetches minified + gzip totals from Bundlephobia; falls back to the npm registry's unpacked size when Bundlephobia is unavailable. Version defaults to latest; pin with @ (e.g. lodash@4.17.21).

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Check the shipped size of npm packages: minified + gzip from Bundlephobia with an npm registry fallback. Compare two packages side by side before adding a dependency.

[x]Features
  • -Minified + gzip totals from Bundlephobia
  • -npm registry fallback with unpacked size
  • -Side-by-side comparison of two packages
  • -Version pinning (e.g. lodash@4.17.21)
  • -Percentage difference readout
  • -Live API checks from the browser
>Use Cases
  • >Evaluating a dependency before adding it
  • >Comparing moment.js vs. date-fns vs. dayjs
  • >Auditing bundle impact for performance budgets
  • >Justifying dependency swaps in code review

Frequently Asked Questions

>Where does the size data come from??
Bundlephobia reports minified + gzip bundle sizes for the main entry point. When it is unreachable, the tool falls back to the npm registry's unpacked size.
>Is gzip size the whole story??
No — it ignores tree-shaking (importing one function of lodash pulls less). For real-world impact, measure your own bundle with a build analyzer.
>Why does the size differ from node_modules on disk??
The registry unpacked size includes all files (types, README, tests). Bundlephobia measures only what gets loaded after bundling and minification.