What is a 7Z file?
7z squeezes files smaller than ZIP, sometimes dramatically so on large sets, and it can lock an archive with a password that hides the file names too. The catch is that whoever receives it needs software that reads 7z. You can turn a 7Z into other formats here, though nothing can be saved back as 7Z.
Specification
| Full name | 7-Zip Archive |
|---|---|
| Extensions | .7z |
| Media type | application/x-7z-compressed |
| Compression | Lossless |
| Transparency | — |
| Animation | — |
| Multiple pages | Supported |
| Colour depth | LZMA and LZMA2 with solid blocks, optional AES-256 |
| Size limits | — |
| Introduced | 1999 |
| Developed by | Igor Pavlov |
| Standard | Open |
| Browser support | Not displayed by browsers |
What 7Z is used for
- Distributing large software packages and game mods
- Long-term storage where archive size matters more than speed
- Encrypted archives that must also hide the list of filenames
- Compressing large collections of similar text or source files
Strengths and limitations
What 7Z does well
- Typically 20 to 40 percent smaller than an equivalent ZIP
- Solid compression exploits redundancy across files, not just within one
- A password can hide the file names as well as the contents
Where 7Z falls short
- No operating system opens it without installing extra software
- Compression is slow and can need a gigabyte or more of memory
- Solid blocks mean extracting one file may decompress a whole group
Convert 7Z to
Every target this format can be written out as, each on its own page.
Tools that accept 7Z
Questions about 7Z
What is a .7z file?
7z squeezes files smaller than ZIP, sometimes dramatically so on large sets, and it can lock an archive with a password that hides the file names too. The extension .7z identifies it, and its media type is application/x-7z-compressed.
How do I open a 7Z file?
Browsers do not display 7Z natively, so you either need software that understands it or you convert it to something more common first. Converting is usually the faster route when you only need to look at the contents once.
Is 7Z lossy or lossless?
Lossless. Nothing is discarded, so repeated saves never degrade the contents.
What is 7Z good for?
Typically 20 to 40 percent smaller than an equivalent ZIP. Solid compression exploits redundancy across files, not just within one. A password can hide the file names as well as the contents. In practice that makes it a good fit for distributing large software packages and game mods, and Long-term storage where archive size matters more than speed.
What are the drawbacks of 7Z?
No operating system opens it without installing extra software. Compression is slow and can need a gigabyte or more of memory. Solid blocks mean extracting one file may decompress a whole group.