Yo' shitheavy?Yosh it!

Yosh squeezes files, folders and backups into small .yosh archives, smaller than ZIP and xz, and gives every byte back exactly as it was.

Download for Windows How it works

Free. Windows 10 and 11, 64-bit. No account, no admin rights. Version 1.5.0.

16 MB down to 1.3 MB

C headers: 92% smaller, and 20% smaller than xz.

Original

16.0 MB

xz -9e

1.7 MB

Yosh

1.3 MB

Measured on real folders, one CPU core, same PC. Yosh takes longer than xz to get there; see speed.

Select. Right-click. Yosh it.

No window to open and no settings to learn. Select as many files and folders as you like, Ctrl+A included, and they go into one archive named after their folder.

Look inside before you unpack
Double-click a .yosh file to browse its folders, then extract everything or just the files you want. Open a single file straight from the archive.
Add to an archive by dragging
Drop files onto a .yosh file and they join it. Nothing is unpacked or repacked, and the original archive is only replaced once the new one is complete.
Right-click it again to get it back
Extract here, extract to a folder, or test the archive without unpacking it. Extraction never overwrites anything: a name that exists gets a number.
Quiet updates, signed by us
Once a day Yosh asks this site whether there is a newer version. Updates install silently and are ignored unless they carry our signature. Switch it off any time.

Small on purpose. You choose the speed.

Yosh uses context mixing, the technique behind the strongest compressors, instead of the LZ method used by ZIP and xz. It finds more to squeeze, and needs more time to do it. Big jobs are split into blocks and packed on all your cores at once; the archive is identical whatever the core count.

Level	Best for	Speed	Size
Fast	Moving something quickly or sending it now	4 to 8 MB/s	Smaller than ZIP, a little bigger than xz
Balanced	Everyday use. This is the default.	About 1 MB/s per core, in both directions	Smaller than xz
Maximum	Archives you keep for years	Slower again, uses more memory	The smallest Yosh makes

Each core in use needs about 300 MB of free memory. Opening one file from a big archive unpacks only as far as that file.

Built to be trusted with your files

A compressor is only worth using if you never have to wonder whether it gave everything back.

Lossless, and checked
Every file and every block carries a checksum. Damage is reported, never hidden. Your originals are never touched.
Nothing leaves your PC
No accounts, no analytics, no uploads. The only network use is the optional daily update check. Read the privacy page.
Installs for you alone
No administrator rights, no services, nothing left running. Uninstall from Settings and it is gone.
Hostile archives stay contained
Yosh refuses archive names that try to escape the destination folder, and never runs programs from inside an archive.