“What about…?” and “How about…?” look almost identical, and sometimes they are interchangeable. But native speakers often use them for slightly different purposes.

The easiest way to remember the difference is:

What about…? → another topic, person, thing, or concern
How about…? → a suggestion or offer

日本語ではどちらも「〜はどう？」と訳されることが多いですが、英語では使い方に少し違いがあります。

1. “How about…?” — Making a suggestion

We often use How about…? when suggesting an idea.

How about pizza for dinner?
夕食にピザはどう？

How about going to the beach tomorrow?
明日、海に行くのはどう？

How about Friday at 3:00?
金曜日の3時はどう？

Think of How about…? as:

💡 “Here’s an idea. What do you think?”

It is also commonly used when offering something:

How about some coffee?
コーヒーはいかが？

How about another piece of cake?
ケーキをもう一つどう？

2. “What about…?” — Bringing up another person or thing

We often use What about…? when someone has mentioned one thing and we want to ask about another.

A: John is coming to the party.
B: What about Mary?
メアリーは？

A: I finished my English and math homework.
B: What about physics?
物理は？

A: The first test was easy.
B: What about the second one?
2つ目のテストは？

Here, What about…? basically means:

❓ “And what is the situation with this?”

3. “What about…?” — Raising a concern

This is another very common use.

A: Let’s spend all our money on a trip!
B: What about the rent?

In other words:

“Wait! Have you considered the rent?”

Another example:

A: Let’s go out tonight!
B: What about your homework?

「宿題はどうするの？」という意味です。相手が忘れていることや、考える必要があることを指摘しています。

Using How about…? in these examples would sound strange because you are not making a suggestion.

4. But sometimes BOTH are possible!

This is where things get a little tricky.

Imagine:

A: I can’t meet on Thursday.

Both of these responses are natural:

B: How about Friday?
B: What about Friday?

Both mean something like 「じゃあ、金曜日はどう？」.

There is a very slight difference in feeling:

How about Friday? → I’m suggesting Friday.
What about Friday? → Have you considered Friday as another possibility?

In normal conversation, however, the difference is often so small that either one is perfectly fine.

The Simple Rule

If you’re not sure which one to use, remember:

💡 HOW ABOUT = suggestion / offer

How about pizza?
How about tomorrow?
How about taking a break?

❓ WHAT ABOUT = another topic / person / concern

What about Mary?
What about the test tomorrow?
What about the rent?

And remember: when suggesting an alternative, either one can often be used.

English is full of expressions that seem to mean exactly the same thing. Often, however, native speakers make small distinctions without even thinking about them.

What about “What about…?” and “How about…?”

Now you know the difference!