Archive Contents Lister
Peek inside a .zip or .tar without extracting — names, sizes, compression ratios and methods.
What is Contents Lister?
A fast inspector for archives. It reports what is inside, how big each entry is, how well it compressed, and whether anything is encrypted.
How it works
For ZIP files the central directory is parsed directly from the end of the file — the same record file managers read — so nothing is decompressed. TAR and .tar.gz files have their 512-byte headers walked in the same way, and the result can be exported as CSV for a spreadsheet.
- Add your files. Drop files (or a whole folder) onto the drop zone. Browsers hand the contents straight to the page, so nothing is uploaded.
- Choose the options. Pick the format, compression, naming rule or split size. Any change re-computes the preview immediately.
- Download the result. Run the tool and grab the archive, the extracted files or the report. Multi-file results come back as a single .zip.
Examples
A 240 MB photo folder → a 52 MB .zip
JPEGs are already compressed, so the archive only saves 10–15% — but adding the folder structure and a manifest makes the upload verifiable.
A download cut off at 1.4 GB
The File Splitter cuts it into 500 MB chunks that fit the host's limit, and the File Joiner reassembles them, refusing any set with a missing part.
A release bundle with checksums
The Manifest Generator writes sha256sum-style lines next to the files, so the recipient can prove the download arrived intact.
Common mistakes
Expecting ZIP to shrink photos, video or audio
Those formats are already compressed; deflate typically saves single digits on them. ZIP is at its best on text, JSON, CSV, logs and source code.
Treating ZipCrypto as real encryption
Traditional ZIP encryption is legacy and breakable. It stops casual snooping only — for secrets, encrypt the contents with AES-256 first.
Renaming extensions to convert a file
Changing .png to .jpg does not change the bytes inside. Some programs will refuse the file, or display garbage. Use a real converter when the format must change.
Splitting without keeping the suffixes
The parts carry .001, .002 … suffixes on purpose: the joiner orders them by number and fails loudly when one is missing, instead of producing a corrupt file.
Frequently asked questions
Can a listing tell me if an archive is corrupt?
It shows whether the index is complete and whether sizes look plausible, but data CRC errors only surface when entries are decompressed — use the ZIP Integrity Checker for that.
Why does a JPEG show a 100% ratio?
It was already compressed, so deflate could not improve it and the entry is effectively stored. High-ratio entries are almost always text, code or structured data.
Is anything written to disk?
No. The archive is read into memory, indexed and discarded; the only thing you can save is the CSV listing.