Download UPX

Ultimate Packer for eXecutables is a free tool designed to reduce the amount of disk space used by a program executable file like EXE or DLL libraries.

Content Summary

  1. What is UPX?
  2. UPX Download
  3. UPX available commands
  4. UPX Alternative

The app is used primarily by developers who want to reduce the size of their apps. Compressing application using UPX is very fast. Compressed EXE files using UPX occupy about half the space on disc, and in some cases are even smaller than the original file by ratio 80%. Everything depends on the content of the original EXE or DLL file.

Screenshot of UPX software running on Windows 10.

You can run and use UPX tool from the command line. Just enter one of the available commands, pointed out the path to the file and the compression level. The program can be used both for home and commercial use.

UPX is my favorite tool to compress (EXE) executable files. The software will reduce the size of DLLs and EXE by around 50%-70%. Programs and libraries compressed using free UPX are completely self-contained and run exactly as before, with no runtime or memory penalty for most of the supported formats.

Ultimate Packer for eXecutables supports a number of different executable formats, including Windows 95/98/ME/NT/2000/XP/CE. I always used UPX to compress my apps I developed in Delphi or Lazarus. UPX download offers installer for Windows 32- and 64-bit version.

To compress an EXE file simply type 'upx app.exe' will compress a program or DLL. For best compression results it is recommended to use brute parametr 'upx --brute program.exe'. Full documentation comes with the UPX app.

UPX available commands

-1 (compress faster)

-9 (compress better)

-d (decompress)

-t (test compressed file)

-l (list compressed files)

-V (display version number)

-h (give more help)

-L (display software license)

-q (be quiet)

-v be verbose

-oFILE (write output file)

-f (force compression of suspicious files)

-k (keep backup files)