FUPX (formerly Free UPX) allows you to compress or decompress EXE, DLL, OCX, BPL, CPL and other files. It offers easy access to all documented and undocumented UPX parameters without the need for accessing the command-line.

The program is an advanced interface for the UPX (Ultimate Packer for eXecutables). It uses the Microsoft Portable Executable and COFF Specification.

Alternatively, FUPX Portable is in PortableApps.com Format and includes both the 32-bit and 64-bit versions of the app.