It allows you to compress (and decompress) files produced according to Microsoft Portable Executable and COFF Specification (EXE, DLL, OCX, BPL, CPL and other). It offers easy access to all documented and undocumented UPX parameters without the need for command line usage.

The Free UPX interface is very simple and user-friendly. To compress executable files, just drag & drop them into main window, select proper profile from list, and click the COMPRESS button.

Free UPX is designed for UPX 3.03w - the last stable version in July 2008.

UPX 是個用於壓縮及解壓縮可執行檔案的工具。在不影響程式原來的執行能力下，最高可達到 50~70% 的壓縮率，大幅縮小檔案容量與磁碟空間，加速網路下載。它能夠壓縮程式內的所有資源，也可以讓您自行調整壓縮率，甚至還內建完整的解壓還原功能。