File Extension Extractor

The File Extension Extractor scans a list of filenames or URLs and pulls out the extension from each one, then tallies how many times each unique type appears. Whether you are looking at a directory listing, a set of download links, or an export from a file manager, you get an instant breakdown of the file types present without opening a spreadsheet or writing a script.

It handles both plain filenames and full URLs, stripping away any query string or fragment before reading the extension so that a link like image.png?width=200 is correctly recognised as a PNG. Paths and folders are ignored too, so only the final file name matters when the extension is determined.

Everything runs locally in your browser with JavaScript, so nothing you paste is uploaded or stored. Developers, sysadmins, and anyone auditing a batch of files can quickly understand the composition of a list and export the results, all while keeping potentially sensitive filenames on their own device.

Features

• Extracts the extension from both bare filenames and full URLs in a single mixed list.
• Strips query strings and fragments before reading the extension so parameters never distort the result.
• Ignores folder paths and keeps only the final file name when determining each extension.
• Counts how many times each unique extension appears, revealing the dominant file types at a glance.
• Optionally lowercases extensions so that variants such as JPG and jpg are grouped together.
• Skips tokens that have no genuine extension, keeping the output focused on real file types.
• Exports the extension table to CSV or XLSX, or copies it to the clipboard for reporting.

How to use File Extension Extractor

1. Paste your filenames or URLs into the input box, one per line or separated by spaces or commas.
2. Leave the lowercase option enabled to merge case variants, or turn it off to keep original casing.
3. Read the table, where each row shows a unique extension and how many items use it.
4. Check the stats to see how many extensions were found in total and how many are distinct.
5. Identify unexpected or unwanted file types that may need filtering or closer inspection.
6. Export the table to CSV or XLSX, or copy it, to document the file mix or feed it into other tools.

Benefits

• Developers summarise the file types in a build output or asset folder within seconds.
• Sysadmins audit a directory listing to understand the composition of a large file set.
• Security reviewers flag unexpected executable or script extensions inside a batch of files.
• Content teams confirm that a media export contains only the intended image or document types.
• Anyone cleaning a file list gets a quick, deduplicated inventory of the extensions present.
• Local processing keeps potentially sensitive filenames and paths private on your own machine.

A file extension is the short suffix after the final dot in a file name, and it usually signals the file's format. Reading it reliably means ignoring everything that is not part of the name itself: this tool discards the scheme, host, and path of a URL, drops any query string or fragment, and then looks only at the last dot in the remaining file name, so links with parameters and deeply nested paths are all handled correctly.

The count is what turns a raw list into insight. Seeing that a folder is ninety percent images with a handful of stray scripts, or that a download set mixes documents and archives, is far more useful than scrolling through the names one by one. Sorting by frequency puts the dominant types first, which is ideal for audits, migrations, and clean-up tasks where you need to understand the shape of a dataset fast.

All processing happens locally in your browser with JavaScript, so your filenames and URLs are never uploaded, which matters when they reveal project structure or internal paths. The tool only treats short alphanumeric suffixes as extensions, so trailing dots, version-style names, and files without an extension are skipped rather than producing misleading entries in the output.