ZIP to 7Z Converter
Convert ZIP to 7Z online for free. Fast, secure archive conversion that preserves folder structure and file integrity. No software installation required.
Up to 50 MB per file. Sign up free to convert files up to 100 MB.
| File name | Size | Convert to |
|---|
Checking files and selected output formats.
ZIP to 7z: upgrading compression efficiency
ZIP's DEFLATE compression uses a 32 KB sliding window and per-file compression. 7z's LZMA2 algorithm uses dictionary sizes up to 1.5 GB and supports solid compression, combining all files into a single stream before compressing. This is especially effective when many files share similar content (source code repositories, document collections). The conversion extracts all files from the ZIP and re-compresses them with LZMA2, typically achieving 30-40% smaller archives for text-heavy content.
Convert ZIP to 7z when storage space is critical and all recipients have 7-Zip or compatible extraction tools. This is common for large software distributions, game mods, and archival storage where the compression savings justify the compatibility tradeoff.
ZIP vs 7Z: Side-by-side
Technical comparison of the two formats, useful for deciding which to use, or for confirming what changes during conversion.
| Property | ZIP | 7Z |
|---|---|---|
| Full name | ZIP Archive | 7-Zip Archive |
| Year introduced | 1989 | 1999 |
| Developer / standard body | PKWARE (Phil Katz) | Igor Pavlov |
| MIME type | application/zip | application/x-7z-compressed |
| File extension | .zip | .7z |
| Compression | DEFLATE (typically) | LZMA / LZMA2 (best ratio of common formats) |
| Color / data depth | N/A | N/A |
| Max dimensions / size | 4 GB per file (ZIP64 extension lifts this) | 16 EB file size |
| Transparency | No | No |
| Animation | No | No |
| Standard / specification | PKWARE APPNOTE / IETF RFC 1951 | 7-Zip (open) |
| Best for | Universal archives, opens natively on Windows, macOS, Linux | Maximum compression, typically 30–50% smaller than ZIP |