“How do you mean?” and “How do you mean that?” have almost the same meaning, but “How do you mean that?” is slightly clearer and more complete. Both are used when you want someone to explain what they just said. “How do you mean?” sounds more British and a little informal. “How do you mean that?” sounds more neutral and is easier for learners to use correctly. You can say “How do you mean that?” in other ways, such as: “What do you mean?” “What do you mean by that?” “Can you explain what you mean?” The most common and natural one in everyday speech is “What do you mean by that?”

Hi Pelin! “How do you mean” is usually used for clarification/more details on the statement being made. For example: Person 1: I think this assignment is too complex. Person 2: How do you mean? What aspects are too complex? Other alternatives: - Can you elaborate? - Why did you say that? - What do you mean? - What do you mean by that? —— “How do you mean that?” is used to ask what the intention behind a statement is when the tone or meaning may be unclear. For example: Person 1: I spilled my coffee. That’s just fantastic! Person 2: How do you mean that? Person 1: I was being sarcastic. (This phrasing isn’t used frequently because it doesn’t sound as natural.)