(I recommend including this disclaimer to manage user expectations, as "decompiling" is often misunderstood)
Before choosing a tool, you must identify what kind of EXE you are dealing with. The tool you need depends entirely on the language the program was written in: exe decompiler online free portable
An interactive online tool that allows you to upload an executable and see equivalent C-like output from multiple popular decompilers simultaneously. (I recommend including this disclaimer to manage user