So, can you convert EX4 to MQ4 for free?

Not truly, legally, or safely—unless you are the original author.

If you’ve been trading with MetaTrader 4, you’ve likely run into this problem: you have a great EA or indicator, but it’s compiled as an . You want to see the source code (MQ4) to modify it, learn from it, or fix a bug.

EX4 to MQ4 Free: What You Need to Know (And Why Most "Free Tools" Are Scams)