Converting (compiled) to (source code) for free is a highly sought-after but technically difficult process. Because modern MetaTrader 4 builds (Build 600+) use advanced compilation that transforms human-readable logic into machine instructions, full "1:1" conversion is considered nearly impossible today.

A 2024 study of 50 "free ex4 to mq4 converter" downloads:

function. This allows you to reference an EX4 indicator's data in a new EA without needing access to the original source code. Summary Table Legacy EX4 (Pre-2014) Modern EX4 (Post-Build 600) Feasibility High (using old tools) Very Low (manual effort required) Code Quality Readable, original logic Broken, random variables, "pseudocode" Primary Method Decompiler 4.0.432 Manual reverse engineering or How can I convert .ex4 file into .mq4? - Forex Factory

: The majority of online sites offering "free" or "updated" converters are noted by experts to be fake, often providing broken code or malicious software.

If you must attempt a conversion, these are the primary (though limited) approaches: Open Source Tools (Advanced) Ghidra or IDA Pro

: Most free automated results produce "gibberish" or flawed code with random variable names and illogical structures that will not compile in MetaEditor. Paid Redirects