What is Npm Package Size Checker
The NPM Package Size Checker is a reference tool that generates a direct link to bundlephobia.com for any npm package name you enter. It does not fetch package data itself — the tool runs entirely client-side with no network access — but it constructs the correct URL for the bundlephobia.com page that shows the package's install size, dependency tree, and export analysis. Enter a package name like lodash, react, or date-fns, and the tool displays the package name along with a clickable link to its bundlephobia page. This serves as a quick lookup tool for developers evaluating dependencies: instead of navigating to bundlephobia.com manually, typing the package name, and waiting for results, you can enter the name here and get a direct link. The tool also includes a note reminding you that real size data requires visiting the linked page, since this tool cannot make external HTTP requests. While this tool cannot fetch real-time data, the link approach has an advantage: bundlephobia.com provides the most up-to-date size information, including the effect of recent version releases on bundle impact. The tool also works as a reference — keep it bookmarked alongside bundlephobia for quick lookups during dependency evaluation sessions.
How to Use Npm Package Size Checker
- Step 1: Type an npm package name into the input textarea (e.g., lodash, react, express, date-fns). Do not include version numbers or scope prefixes unless you want to check a specific version.
- Step 2: Click Transform. The tool displays the package name and a link to its bundlephobia.com page.
- Step 3: Copy the link or click through to bundlephobia.com to see the full size analysis including install size, dependency count, and export-by-export breakdown.
Why Use Npm Package Size Checker
Before adding a new npm dependency, checking its bundle impact is a standard part of responsible development. bundlephobia.com is the go-to resource for this, but navigating to it and entering package names adds friction to what should be a quick check. This tool provides a shortcut: type the name, get the link, click through. It is especially useful during code review — when reviewing a PR that adds a new dependency, you can quickly generate the bundlephobia link and paste it into the review comment, giving the team immediate visibility into the size impact. Additionally, the bundlephobia page shows the package's dependency tree, which is critical for understanding transitive size impact — a small package with many large dependencies can have a surprisingly big footprint.
Privacy & Security
This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.
Frequently Asked Questions
Why can't this tool fetch the size data directly?
<p>The tool runs entirely in the browser with no server backend, and it does not have permission to make cross-origin HTTP requests to bundlephobia.com or the npm registry. The link approach is the simplest way to provide size information without requiring network access.</p>
Can I check scoped packages?
<p>Yes — enter the full package name including the scope (e.g., @angular/core, @vue/compiler-sfc). The bundlephobia URL will be constructed correctly.</p>
Does it support checking specific versions?
<p>The tool links to bundlephobia.com which supports version-specific analysis via URL parameters. After navigating to the page, you can select the version you need from bundlephobia's interface.</p>