Add your CPIO file
Drop one or more .cpio files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Repacking a .cpio archive as .tar.gz moves the same files into a container with different compression and compatibility trade-offs. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Repacking a .cpio archive as .tar.gz moves the same files into a container with different compression and compatibility trade-offs. A .cpio file is a Unix archive of the same vintage as TAR, built from a header-then-data record for each file with no compression and no index. It survives mainly because two things still depend on it: RPM packages and Linux initramfs images.
A .tar.gz file is a tarball that has then been run through gzip: tar supplies the multi-file bundling and Unix metadata, gzip supplies the compression. This two-layer pairing is the default distribution format of the open-source world. For this route the practical draw is solid-style compression across the whole file set and full Unix metadata preservation through the tar layer — balanced against no random access to individual members, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .cpio, several mutually incompatible header formats share the extension. Switching to .tar.gz buys you solid-style compression across the whole file set, which is why it is the better fit for source releases — nearly every GitHub release tarball. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | CPIO archive (.cpio) | Gzipped TAR archive (.tar.gz) |
|---|---|---|
| Format type | Container — quality depends on the codecs and settings inside | Container — quality depends on the codecs and settings inside |
| How it stores data | the "new ASCII" format (magic 070701) is the modern one: a 110-byte header of hexadecimal ASCII fields, then the filename, then the data, each padded to a four-byte boundary | compression applies to the tar stream as a whole — effectively solid compression, beating ZIP's per-file approach on collections of small similar files |
| Strongest at | extracting the payload of an RPM package | source releases — nearly every GitHub release tarball |
| Weak spot | several mutually incompatible header formats share the extension | no random access to individual members |
| Metadata | mode, ownership and timestamps are present in the headers and are read; ZIP output keeps paths and sizes, which are the parts it can represent | ownership, permission modes, and timestamps come from the inner tar layer; the gzip wrapper contributes only its own optional filename and mtime fields |
Drop one or more .cpio files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .tar.gz in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if TAR.GZ is selectable, the route is real and validated.
Press Convert. Extraction and repacking use WebAssembly builds of real archive engines (libarchive and fflate) running in your browser.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid TAR.GZ file. Outputs keep the original filename with the .tar.gz extension.
Since cpio is container-oriented and tar.gz is container-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .tar.gz itself requires.
Yes — the .cpio file is processed inside your browser tab and never uploaded. Extraction and repacking use WebAssembly builds of real archive engines (libarchive and fflate) running in your browser. Close the tab and the file is gone from memory.
One command — tar -xzf — unpacks it on any Linux or macOS box, Windows 10+ includes bsdtar for the same job, and recent Windows 11 builds open tarballs from File Explorer. GUI archivers on all platforms recognize both the .tar.gz and .tgz spellings.
It depends on the content: compression applies to the tar stream as a whole — effectively solid compression, beating ZIP's per-file approach on collections of small similar files. Convert one representative file first and compare before batch-processing a large set.
In .cpio, mode, ownership and timestamps are present in the headers and are read; ZIP output keeps paths and sizes, which are the parts it can represent. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.