The Difference Between 「いいです」は許可？拒否？ネイティブ感覚との違い｜Japanese Grammar (N5–N3)

(Joy smiling and giving permission to use a pen [YES] vs. Joy waving her hand to decline more coffee [NO])

“Can I use this?” -> Hai, ii desu yo. (Yes, that is fine.)
“Do you want a bag?” -> Iie, ii desu. (No thank you, I am good.)
One of the most confusing moments for a beginner in Japan is offering something to someone, hearing them say “Good” (いいです – Ii desu), and then watching them walk away! Just like the English phrase “I’m good,” the Japanese phrase “Ii desu” can mean both approval (YES) and refusal (NO). The secret to understanding native speakers is paying attention to the clues attached to the phrase. Let’s look at how Joy handles both situations!

🗣 Conversation Scene

Joy and Ken are working at the office. Ken asks Joy for a favor, and then offers her a drink.

Scene A: Asking for Permission (YES)

Ken

Joyさん、このペンを使ってもいいですか？
(Joy, is it okay if I use this pen?)

Joy

はい、いいですよ。どうぞ。
(Yes, “ii desu yo” [it is fine]. Go ahead.)

Scene B: Offering Something (NO)

Ken

Joyさん、コーヒーもう一杯いかがですか？
(Joy, would you like another cup of coffee?)

Joy

あ、いいえ、いいです。お腹がいっぱいです。
(Ah, no, “ii desu” [I am good / no thank you]. I am full.)

💡 Explanation

Approval vs. Polite Refusal

⚠️ The Golden Rule of “Ii desu”:
Never say “Ii desu” with a flat robot voice! If you want to say YES, smile and add “Hai” or “yo.” If you want to say NO, gently shake your head or add “Iie” or “Daijoubu desu.”

1. いいです (Ii desu) = YES / Permission 👍

Focus: Accepting or Approving.
When responding to a request for permission (e.g., “Can I sit here?”), “Ii desu” means “Yes, that is good.” To make sure there is no misunderstanding, native speakers almost always attach “Hai” (Yes) to the front, or “yo” (assertion particle) to the end.

はい、いいですよ。
(Yes, it’s fine! *Very clear permission*)
これでいいです。
(This one is good. *Selecting an item you like*)

2. いいです (Ii desu) = NO / Polite Refusal ✋

Focus: Declining an offer.
When someone offers you an item or a service (e.g., a plastic bag at a convenience store, or a refill of water), “Ii desu” acts exactly like “I’m good” in English. It means your current state is already good, so you do not need anything more. It is a polite way to decline.

いいえ、いいです。
(No, I’m good/No thank you. *Clear refusal*)
大丈夫です。いいです。
(It’s okay. I’m good. *Soft and polite refusal*)

📊 Comparison Table

Situation	Meaning	Best Phrasing to Avoid Confusion
Someone asks for permission (e.g., Can I open the window?)	YES (That is fine)	はい、いいですよ。 (Hai, ii desu yo)
Someone offers you something (e.g., Do you want a receipt?)	NO (No thank you)	いいえ、いいです。 (Iie, ii desu) + hand wave

🚧 The Convenience Store Trap

In Japanese convenience stores, clerks talk very fast. They will ask, “Fukuro wa irimasu ka?” (Do you need a bag?). If you just mumble “Ii desu” without shaking your head, the clerk might get confused and have to ask you again to clarify if you meant “Yes, a bag is good” or “No, I am good.” Always use a clear head shake or say “Daijoubu desu” (I am okay) to be instantly understood!

🔥 Practice Quiz

Tap to check the answer!

Q1. A coworker asks, “Koko ni suwatte mo ii desu ka?” (Can I sit here?). You want to let them sit. What do you say?
A. Iie, ii desu.
B. Hai, ii desu yo.

Answer: B (Hai, ii desu yo)
You are giving permission, so you should use the positive “Hai” and “yo”.

Q2. A waiter offers you a menu for dessert. You are already full and want to decline politely. What do you say?
A. Hai, ii desu yo.
B. Aa, iie, ii desu.

Answer: B (Aa, iie, ii desu)
You are refusing an offer. Saying “Iie” (No) makes it clear that you mean “No thank you.”

Keep practicing with JPLT!