Archive Converter
Repack compressed archives between ZIP, 7z, TAR, and RAR. Bundle, recompress, and prepare files for download — free and private.
Popular conversions
All supported formats
Bundling and compressing are separate jobs
Archive formats do two things that people tend to run together. Bundling puts many files into one. Compressing makes data smaller. Some formats do both, and some do only one.
TAR bundles and does not compress. GZ, BZ2, XZ, and ZST compress a single stream and know nothing about file names or directories. That is exactly why `.tar.gz` has two extensions: TAR gathers the files into one stream, then GZIP compresses that stream. ZIP and 7z do both jobs in a single format, which is why they are what people actually send each other.
| Format | Character |
|---|---|
| ZIP | Universal — opens on every OS with no extra software. Modest compression. |
| 7z | Much better compression, especially on large or repetitive data. Needs software. |
| TAR | Bundling only. Preserves Unix permissions and symlinks. |
| GZ | Fast single-stream compression. The web and log-rotation default. |
| BZ2 | Smaller than GZ, noticeably slower. Largely superseded. |
| XZ | Very high compression, slow. Source tarballs and OS images. |
| ZST | Near-GZ speed with much better ratios. The modern choice. |
| RAR / ISO | Read-only here — we can open and repack them, but not write them. |
When repacking actually saves space
Compression finds redundancy. If the data has already had its redundancy removed, there is nothing left to find — so a ZIP full of JPEGs, MP3s, MP4s, or PDFs will barely shrink when converted to 7z. People often read that as the conversion having failed. It worked; there was simply nothing there.
Repacking pays off on uncompressed or repetitive data: text, logs, CSVs, source code, database dumps, BMP and WAV files, and directories of near-identical files. On a large log archive, ZIP to 7z or XZ can genuinely halve the size.
What the conversion does
Repacking fully decompresses every file inside and compresses it again with the new algorithm. The contents come out byte-identical; only the archive's size changes. It all happens inside a temporary directory that is removed afterwards even if the job fails.
Two constraints follow from the bundling/compressing split. Converting a multi-file archive into a single-file compression format only works if the archive contains exactly one file — otherwise the job stops with a clear error rather than silently dropping the rest. Going the other way, a .gz is decompressed to a temporary file and packed as the new archive's single entry.
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Frequently asked questions
- Why didn't my archive get smaller when I converted it to 7z?
- Because what is inside was already compressed. JPEGs, MP3s, MP4s, and PDFs have had their redundancy removed already, so a second compression pass gains a percent or two at best. Repacking pays off on text, logs, source code, and other uncompressed data.
- Can I convert a ZIP with many files into a .gz?
- Only if the ZIP contains exactly one file. GZ wraps a single stream and has no concept of multiple entries or directories, so an archive with more than one file stops with a clear error rather than silently discarding the rest.
- Can I create a RAR file?
- No. RAR is proprietary — it can be opened and its contents repacked as ZIP or 7z, but creating one requires the commercial tool. The same applies to ISO disc images: readable, not a write target.
- Which format should I send to someone else?
- ZIP. It opens on every machine with no software and no instructions, and that is worth more than the space 7z would save. Use 7z or tar.xz when you are archiving compressible data for yourself.
- Is the Archive Converter free?
- Yes, every conversion is completely free with no account and no watermark.
- Do I need to install anything?
- No. Use the tool from your browser; files are uploaded to our servers for processing.
- Are my files safe?
- Files are auto-deleted after 2 hours and are never shared.