beruto o shinai to, kono zubon wa sukoshi ookii desu.

topic particle

Breakdown of beruto o shinai to, kono zubon wa sukoshi ookii desu.

• です: to be
• 大おおきい: big
• と: conditional particle

Questions & Answers about beruto o shinai to, kono zubon wa sukoshi ookii desu.

What does ベルトをしないと mean here?

Here, ベルトをしない means not wear a belt, and と means if/when.

So ベルトをしないと means:

• if I don’t wear a belt
• unless I wear a belt
• without a belt

In this sentence, it connects to the result in the second half: if no belt is worn, the pants feel a little big.

Doesn’t 〜ないと often mean have to?

Yes, it often does, so this is a very common point of confusion.

For example:

• 行かないと。 = I have to go.
• 勉強しないと。 = I have to study.

That usage is actually a shortened form of expressions like:

• 〜ないといけない
• 〜ないとだめ

But in your sentence, 〜ないと is not being used that way.
It is a normal conditional:

• ベルトをしないと、このズボンは少し大きいです。
• If I don’t wear a belt, these pants are a little big.

So whether 〜ないと means if not or have to depends on what comes after it.

Why is the particle を used after ベルト?