Tylenol (acetaminophen) 4 120mg is equel to how mg diluted?

Not sure what u mean. I'm not sure if I am understanding your question correctly: If you dilute 120mg of Tylenol (acetaminophen) #4 in any amount of liquid, but still drink the entire amount, it is still equal to 120mg of Tylenol (acetaminophen) #4.