ZIP is the most compatible archive format and opens on almost every device without extra software, 7Z usually produces the smallest files and has strong AES-256 encryption, RAR adds recovery records but needs WinRAR to create, and TAR.GZ is the standard on Linux because it keeps Unix permissions. For sharing with anyone, choose ZIP; for maximum compression or encrypted backups, choose 7Z; for Linux systems and servers, choose TAR.GZ or TAR.XZ.
- ZIP opens natively on Windows, macOS, Linux desktops, iOS and Android, which makes it the safe default for sharing.
- 7Z with LZMA2 typically compresses text, code and documents noticeably better than ZIP, at the cost of speed and compatibility.
- RAR is proprietary: anyone can extract it, but creating RAR files requires WinRAR or its command-line version.
- TAR is a bundling format; the .gz, .bz2 or .xz suffix names the compressor applied on top of it.
- Photos, videos, music and Office files are already compressed, so no archive format will make them much smaller.
- An encrypted ZIP still shows its file names; 7Z and RAR can hide them too.
An archive does two jobs: it bundles many files and folders into one file, and it usually compresses them. The formats below make different trade-offs between compression ratio, speed, compatibility and security, and the right choice depends far more on who will open the file than on squeezing out the last few kilobytes.
ZIP: the universal format
ZIP was created by Phil Katz's company PKWARE in 1989, and its specification (the PKWARE "APPNOTE") is publicly documented. Each file inside a ZIP is compressed separately, almost always with the Deflate algorithm, and a central directory at the end of the archive lists every entry. Because files are stored independently, a program can extract a single file quickly without reading the rest, and damage to one entry does not necessarily ruin the others.
Its strength is reach. Windows File Explorer, macOS Finder, most Linux desktops, iOS and Android all open ZIP files without installing anything, and many other formats are ZIPs in disguise: .docx, .xlsx, .pptx, .epub, .jar and .apk files are ZIP archives with a particular internal structure.
Points to know about ZIP:
- Encryption comes in two kinds. The original ZipCrypto scheme is weak and vulnerable to known-plaintext attacks. The newer AES-256 extension is strong, but Windows File Explorer cannot open AES-encrypted ZIPs, so recipients usually need 7-Zip, WinRAR or another full-featured archiver.
- File names stay visible. With standard ZIP encryption, the contents of each file are encrypted but the names, sizes and dates in the directory are not. Anyone can list what is inside without the password.
- Large files and Unicode names. The ZIP64 extension removes the old 4 GB limits, and a UTF-8 flag allows non-Latin file names. Archives made by old tools without that flag can show garbled names when opened on a system with a different language setting.
You can make one in the browser with our Create ZIP tool, which offers an optional AES-256 password, and open one with Unzip Files.
RAR: proprietary, with recovery records
RAR was developed by Eugene Roshal and is the native format of WinRAR. The current version of the format, RAR5, replaced the older RAR4 format and uses AES-256 for encryption. The decompression code is freely available, which is why many programs can extract RAR files, but the compression algorithm is not licensed for other software to create RAR archives. In practice you need WinRAR (or the rar command-line program) to make one.
RAR has features that kept it popular for distributing large files:
- Recovery records store extra redundancy data so that a partly damaged archive can be repaired.
- Multi-volume archives split one archive into parts (
.part1.rar,.part2.rarand so on) that are extracted together. - Solid compression treats many files as one continuous stream, which improves compression for collections of similar files.
- File name encryption can hide the list of contents until the password is entered.
If you receive a RAR and have nothing to open it, our RAR extractor handles RAR4 and RAR5 archives in your browser, and RAR to ZIP converts one into a format everybody can open.
7Z: the best compression for most data
7Z is the native format of 7-Zip, a free and open-source archiver by Igor Pavlov. It normally uses LZMA or LZMA2, algorithms that keep a large dictionary of data already seen and encode repeats very compactly. On text, source code, logs, databases and uncompressed images, 7Z archives are typically clearly smaller than ZIP archives of the same files. The trade-off is that compression is slower and uses more memory, especially at the highest settings.
7-Zip creates solid archives by default, and it supports AES-256 encryption. When creating a 7Z archive in 7-Zip you can also tick Encrypt file names, which encrypts the archive header so that nobody can see what the archive contains without the password.
The weakness is compatibility. Recipients on older Windows versions, macOS or phones usually need an extra app. Our Create 7Z tool builds LZMA-compressed archives in your browser (without a password option); use 7-Zip itself when you need an encrypted 7Z.
TAR.GZ, TAR.XZ and TAR.BZ2: the Unix way
TAR (short for tape archive) does not compress anything. It concatenates files into one stream and records each file's path, size, modification time, Unix permissions, owner and group, and symbolic links. That metadata is why TAR is the standard for Linux software, server backups and source code releases: extracted files keep their executable bits and ownership, which ZIP handles poorly.
The compression is a separate step applied to the whole TAR stream, and the extension tells you which compressor was used:
- .tar.gz or .tgz uses gzip, which is based on the same Deflate algorithm as ZIP. It is fast and supported everywhere.
- .tar.bz2 uses bzip2, which usually compresses better than gzip but is slower.
- .tar.xz uses xz, based on LZMA2, giving compression similar to 7Z.
Because the compressor sees all files as one stream, a tarball is effectively solid. That helps compression, but extracting a single file means decompressing everything before it, and corruption early in the file can affect everything after it. TAR has no built-in encryption; on Linux it is usually combined with a separate tool such as GnuPG. Linux and macOS include the tar command, and Windows 10 and 11 ship one as well:
tar -czf project.tar.gz project/ # create a gzip tarball
tar -cJf project.tar.xz project/ # create an xz tarball
tar -xf project.tar.gz # extract (compression is detected automatically)To make one without a terminal, use our TAR.GZ creator.
ISO: a disc image, not a compressed archive
An ISO file is a sector-by-sector image of an optical disc file system (ISO 9660 or UDF). It is not compressed and has no encryption. ISO files are mainly used for operating system installers and software that expects a disc. Windows and macOS can mount an ISO with a double-click so that it appears as a drive, and Linux can mount it with a loop device. You would rarely choose ISO for ordinary file sharing.
Comparison table
| ZIP | RAR (RAR5) | 7Z | TAR.GZ / TAR.XZ | |
|---|---|---|---|---|
| Typical compression | Good (Deflate) | Very good | Very good to excellent (LZMA2) | Good (gzip) / very good (xz) |
| Speed | Fast | Moderate | Slower at high settings | Fast (gzip) / slow (xz) |
| Open format | Yes, documented | No, proprietary | Yes, open source | Yes |
| Who can create it | Almost any tool | WinRAR or rar only | 7-Zip and many others | Any Unix system, many tools |
| Encryption | AES-256 or weak ZipCrypto | AES-256 | AES-256 | None built in |
| Can hide file names | No (standard ZIP) | Yes | Yes | Not applicable |
| Keeps Unix permissions | Partly, tool-dependent | Partly | Limited | Yes |
| Extract one file quickly | Yes | Not in solid mode | Not in solid mode | No |
| Recovery data | No | Yes (recovery records) | No | No |
Built-in operating system support
| System | Opens natively | Usually needs an app for |
|---|---|---|
| Windows 10 | ZIP, ISO (mount); TAR via the command line | RAR, 7Z, TAR.GZ in Explorer, AES-encrypted ZIP |
| Recent versions of Windows 11 | ZIP, RAR, 7Z, TAR, TAR.GZ and other common formats, ISO (mount) | AES-encrypted ZIP and other password-protected archives |
| macOS | ZIP, TAR, TAR.GZ, ISO (mount) | RAR, 7Z |
| Linux desktops | ZIP, TAR and its compressed variants, ISO; often 7Z and RAR via installed packages | Depends on the distribution |
| iOS and Android | ZIP in the built-in file apps | RAR, 7Z and most others |
Recent versions of Windows 11 added native support for opening RAR, 7Z and TAR-based archives in File Explorer, which has made those formats easier to share with Windows users. Do not assume every recipient has an up-to-date system, though; ZIP remains the only format you can send to anyone without a second thought.
Why some files barely shrink
Compression works by finding and removing redundancy. JPEG and HEIC photos, MP4 and MOV videos, MP3 and AAC audio, PNG images and PDF files already compress their data internally, and Office files are ZIP archives themselves. Feeding them into any archiver typically saves very little, sometimes nothing, whichever format you pick. For a folder of holiday photos the difference between ZIP and 7Z is usually negligible, so compatibility should decide.
Plain text, CSV exports, logs, source code, uncompressed images such as BMP or TIFF, and virtual machine disks are the opposite: they compress well, and this is where 7Z and TAR.XZ pull clearly ahead of ZIP. If you need smaller media files, compress the media itself, for example with our image compressor.
Which format to choose
| Situation | Best choice | Why |
|---|---|---|
| Email attachment or sharing with anyone | ZIP | Opens everywhere without extra software |
| Sharing confidential files | 7Z with encrypted file names, or ZIP with AES-256 | Strong encryption; 7Z also hides the file list |
| Long-term personal backup | 7Z or ZIP | Open formats with free tools that will remain available |
| Linux servers, software releases, home directories | TAR.GZ or TAR.XZ | Preserves permissions, ownership and symlinks |
| Smallest possible download of text-heavy data | 7Z or TAR.XZ | LZMA-based compression |
| Large multi-part distribution needing repair data | RAR | Recovery records and volumes |
| Operating system installer | ISO | Expected by installers and virtual machines |
To change formats later, our archive converter turns RAR, 7Z, TAR and ISO files into ZIP, 7Z, TAR variants and more, all in your browser. For encryption choices in detail, see how to password protect a PDF, Word, Excel or ZIP file.
Frequently asked questions
Is 7Z better than ZIP?
For compression ratio and encryption options, usually yes: 7Z typically produces smaller archives and can hide file names. For compatibility, no: ZIP opens on virtually every device without extra software. Choose 7Z for your own backups or technical recipients and ZIP for everyone else.
Is RAR better than 7Z?
Compression is broadly similar, and which one wins depends on the data and settings. RAR offers recovery records; 7Z is free and open source, and anyone can create it. Unless you need recovery records, 7Z is generally the more practical choice.
Can I open RAR or 7Z files without installing software?
On recent versions of Windows 11 you can open them directly in File Explorer. On other systems you can use a browser-based extractor such as ours, which processes the archive locally without uploading it.
Why didn't zipping my videos make them smaller?
Video, photo and audio formats are already compressed, so there is little redundancy left to remove. To reduce their size you need to re-encode them at a lower quality or resolution, not archive them.
What is the difference between .tar.gz and .tgz?
None. Both are a TAR archive compressed with gzip; .tgz is simply a shorter extension.
Can a ZIP file hide the names of the files inside it?
Not with the standard ZIP encryption that common tools support. If the file names themselves are sensitive, use a 7Z archive with header encryption, or put the files inside a ZIP and then encrypt that ZIP inside another one.