Convert ZIP Archive (.zip) to 7-Zip Archive (.7z) online for free. Fast, secure archive conversion with no watermarks or registration.
Upload your .zip file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .7z file when it's ready.
ZIP is the most universally supported archive format, created by Phil Katz in 1989 and built into every modern operating system. ZIP uses DEFLATE compression and per-file storage, enabling random access to individual entries. 7Z uses LZMA and LZMA2 algorithms from the 7-Zip project that consistently deliver 20-40% better compression than ZIP's DEFLATE.
Converting ZIP to 7Z recompresses your universally compatible archive using the most efficient general-purpose compression available. This conversion targets storage optimization — when you need to minimize archive footprint for cloud storage, archival repositories, or bandwidth-constrained transfers and the recipient has 7-Zip or p7zip available for extraction.
7Z's LZMA2 compression produces meaningfully smaller archives than ZIP's DEFLATE across virtually all data types. For a 100 MB ZIP of source code, the 7Z equivalent might be 60-70 MB — a 30-40% reduction. For organizations storing thousands of ZIP archives on cloud platforms where every gigabyte has a monthly cost, the savings compound into significant budget impact.
7Z's solid archive mode adds another compression advantage. ZIP compresses each file independently, unable to exploit redundancy between files. 7Z's solid mode treats multiple files as a single data block, dramatically improving compression when files share content — common in source code, documentation sets, and configuration bundles. A ZIP containing 100 similar configuration files may compress 50-60% better as a solid 7Z.
The ZIP archive is read by parsing the central directory (located at the end of the file) to enumerate all entries. Each file is decompressed from its individual DEFLATE stream, CRC32-verified, and placed in a temporary directory. The extracted file tree is then packed into a 7Z archive using LZMA2 compression with solid mode enabled by default. LZMA2 uses dictionary sizes up to 64 MB, Markov chain modeling, and range coding to achieve compression ratios that DEFLATE cannot approach.
Entirely lossless. Every file from the ZIP is extracted (CRC32-verified) and repacked into 7Z with identical byte content. No data is altered. The 7Z output will be 20-40% smaller than the ZIP while containing bit-for-bit identical files. The improvement comes entirely from the more efficient compression algorithm.
| Device | ZIP | 7Z |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
ZIP to 7Z conversion trades universal compatibility for 20-40% better compression and optional AES-256 encryption. Ideal for archival storage, large collections, and environments where 7-Zip is available.
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| No |
| Egenskap | ZIP | 7Z |
|---|---|---|
| Fullt navn | ZIP Archive | 7-Zip Archive |
| Filendelse | .zip | .7z |
| Best egnet for | Universal support | High compression |