npm Package Size Checker

Every kilobyte your users download slows page load times, especially on mobile and slow networks. Smaller bundles mean faster Time to Interactive (TTI), better Core Web Vitals scores, and improved SEO rankings. A single large package can double your app's bundle size.

Minified size is the package after whitespace and comments are removed. Gzipped size is what's actually transferred over the network — modern servers compress responses with gzip or brotli. Gzipped size is the number that matters most for performance.

Use tree-shakeable packages (look for ES module exports), import only what you need (e.g., 'import get from lodash/get' vs 'import _ from lodash'), choose lighter alternatives (dayjs vs moment), use dynamic imports for code splitting, and audit with tools like bundlephobia before adding new dependencies.

Yes! Enter the package name with the version, e.g. '[email protected]' or '[email protected]'. This lets you compare bundle sizes between versions to see if upgrading will affect your bundle.