A free online tool that checks ZIP, TAR.GZ, TGZ, TAR, and GZIP files for corruption or truncation — including archives over 2 GB. Validation runs entirely on your device, so even huge files don't need to be uploaded anywhere.
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About this tool
Archive Integrity Check verifies whether a compressed archive is structurally sound — useful for confirming a download finished cleanly, a backup is readable, or a file you're about to share isn't corrupted. Unlike most online validators, files never leave your device. The check happens entirely in your browser using the File API and built-in decompression, which is also why there is no upload size limit. Multi-gigabyte archives validate at the speed of your CPU rather than your internet connection.
Supported formats
ZIP — including ZIP64 for archives over 4 GB. Validates the End of Central Directory record, every central directory entry, and spot-checks local file headers.
TAR.GZ and TGZ — streaming gzip decompression with full walk of every TAR header, checksum verification, and entry-size sanity.
TAR — same TAR walk, without the gzip layer.
GZIP (.gz) — full gzip stream decompression; the format's built-in CRC32 catches corruption automatically.
What "valid" means here
A valid result means the archive's internal structure is intact: every header is well-formed, sizes add up, signatures match, and decompression completes without errors. This catches truncation, corruption, and damaged headers, which covers the vast majority of "is this file broken?" questions. It does not separately verify the content of each compressed file against a checksum unless the format itself stores one (ZIP and GZIP do; TAR does not).
Frequently asked
Are my files uploaded anywhere?
No. Validation runs entirely in your browser. Open the network tab in your dev tools and confirm — there's no request that carries your file data.
Is there a file size limit?
None imposed by this tool. The validator streams data in fixed-size chunks, so memory use stays flat regardless of file size. We've tested with files over 10 GB.
Why does my browser show a dialog when I pick a folder?
That's a built-in browser warning whenever a page uses the folder picker. It can't be suppressed by any website. Your files are still never uploaded — the warning just describes the technical capability, not what we do with it.
What if Brave or Firefox refuses to read a dropped folder?
Some browsers restrict folder drag-and-drop. If you see a read error after dropping a folder, drag the archive files directly instead of the parent folder, or use the folder picker button.