This little (cross-platform) executable compression tool Ultimate Packer for eXecutables (UPX) can greatly reduce the size of (static build) executables. The executable filesize will be reduced to the size of a ZIP file containing the same executable.
The tool is very easy to use, just drag-and-drop your executable onto the upx.exe to use the default (fast) compression option of the tool, or type “upx <filename>” in the command-line. Adding the (much slower) “–utra-brute” command-line argument will reduce the filesize even further.
A static build Qt5.1.1 MinGW compiled application with a filesize of 12.972.032 bytes (12.3MB):
DEFAULT: 12.972.032 bytes (12.3MB) is reduced to 5.218.816 bytes (4.97 MB) using the (fast) default settings.
ULTRA-BRUTE: 12.972.032 bytes (12.3MB) is reduced to 4.488.704 bytes (4.28 MB) using the (much slower) “–ultra-brute” argument.