PECompact compresses Windows modules (EXE, DLL, SCR, etc..) substantially, while leaving them able to be run just as before. At runtime, compressed modules are rapidly decompressed in memory. Smaller (<50%) size usually means quicker load time. PECompact generally compresses files much smaller than if they had been compressed by modern data compression software such as RAR. This is accomplished by restructuring and pre-processing that make modules more compressible. Compression also adds a layer of security to modules that resists tampering and reverse engineering.

PECompact supports multiple compression formats, including LZMA, through the use of CODEC plug-ins. Custom loaders (decompression) stubs and API hook plugins are also able to be utilized. Advanced configuration includes selection of resource types that should be compressed as well as other parameters that offer a great deal of control over how modules are compressed. A GUI and console mode application that supports wildcards and directory recursion are included.

The Freeware (Student) Version may only be used to compress modules that will not be sold or bartered in any way.