Add your ZST file
Drop one or more .zst 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 .zst 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 .zst archive as .tar.gz moves the same files into a container with different compression and compatibility trade-offs. A .zst file is a Zstandard-compressed stream. Zstandard hits roughly Gzip's ratio at several times the speed, and much better ratios when asked, which is why it has been quietly replacing Gzip across Linux distributions, databases and network protocols since about 2016.
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 .zst, older tools still do not recognise it, so a .zst can be an obstacle rather than a convenience. 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 | Zstandard stream (.zst) | 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 frame magic is 28 B5 2F FD, followed by a frame header that may or may not declare the decompressed size — a decoder cannot assume it is there | 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 | unpacking an Arch Linux or Debian package payload | source releases — nearly every GitHub release tarball |
| Weak spot | older tools still do not recognise it, so a .zst can be an obstacle rather than a convenience | no random access to individual members |
| Metadata | zstandard carries no file metadata of its own; anything preserved comes from the TAR inside it | 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 .zst 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 zst 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 .zst 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 .zst, zstandard carries no file metadata of its own; anything preserved comes from the TAR inside it. 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.