Compare compression on your files
Which is smaller for your data, ZIP or 7z? Is Zstandard worth it over gzip or xz? Drop your files and they are compressed with every common format side by side, with the size, the time to pack and the time to unpack. Nothing is uploaded.
Times are measured in this browser tab on one CPU core. Native tools that use several cores pack faster, but the order between methods stays about the same. Every result is unpacked and checked once to time it.
How to compare compression formats
- Drop the files or the folder you want to pack. Use real data: how well something compresses depends entirely on what it is.
- Untick any methods you do not need, and press Compare. Each method runs in turn, and the table fills in as results arrive, smallest first.
- Save the winner straight from the table. Every file in it has been unpacked once and checked.
What is compared
- ZIP (Deflate) opens on every computer without extra software. Each file is compressed on its own, which is quick but misses repeats across files.
- 7z with LZMA2 compresses all files as one block, so similar files help each other. Usually the smallest result, but slow to pack. PPMd often wins on plain text.
- gzip, bzip2, xz, Zstandard, Brotli and LZ4 compress a single stream. Several files are packed into one TAR first, as
tar.gz,tar.xzandtar.zstfiles are.
Rules of thumb
To send files to anyone: ZIP. For the smallest download: 7z or xz. For backups and builds you unpack often: Zstandard, which unpacks faster than xz at a size close to it. For web assets: Brotli. When speed is all that matters: LZ4. Photos, video, music and existing archives are already compressed, and no method will shrink them much.
Frequently asked questions
Are my files uploaded?
No. Compression runs in your browser with 7-Zip compiled to WebAssembly (the 7-Zip-zstd edition, which adds Zstandard, Brotli and LZ4). The results are kept in your browser's temporary storage until you leave the page.
Is ZIP or 7z smaller?
7z is usually smaller, because it compresses all files together with a stronger method. The gap depends on the data: in our own test a folder of 60 web pages packed to under a third of the ZIP's size as 7z, while a single large JavaScript file came out about 17% smaller. On files that are already compressed the two end up about the same. Drop your own files above to see the difference for them.
Is Zstandard better than gzip?
At its default level 3, Zstandard packs and unpacks much faster than gzip, at a size that can land either side of it: smaller on a folder of web pages in our test, a little larger on a single JavaScript file. At level 19 it comes close to xz while still unpacking faster.
Why are the times slower than on my computer?
The browser runs each method on a single core, while native tools such as zstd or 7-Zip can use all of them. Compare the methods with each other rather than with a desktop tool.
Can I make these archives on this site?
Yes. Every result has a Save link. To choose the format and add a password, use the ZIP and archive creator, which makes ZIP, 7z, TAR.GZ, TAR.XZ, TAR.ZST and more.