かなり vs なかなか

JLPT N3 vocabulary · what is the difference?

かなり is a neutral "quite, considerably" that simply states a high degree: この問題はかなり難しい。なかなか adds the speaker's surprise or admiration — なかなかおいしい means "this is better than I expected". The trap is that なかなか with a negative means something else entirely: "not easily, not for ages", as in バスがなかなか来ません.

When to use each

かなり

Use かなり to state that the degree is high, with no attitude attached. It works with good and bad things alike (かなり高い, かなり危ない) and is safe in neutral or written contexts where you do not want to sound as if you are judging.

この問題はかなり難しいです。
このもんだいはかなりむずかしいです。
This problem is quite difficult.
駅まではかなり時間がかかります。
えきまではかなりじかんがかかります。
It takes a considerable amount of time to get to the station.

Full entry for かなり

なかなか

In affirmative sentences, use なかなか to praise something that beat your expectations: なかなかいい, なかなか上手ですね. With a negative it has a different job entirely — it says something is slow to happen or hard to achieve, as in なかなか覚えられません.

この料理はなかなかおいしいですね。
このりょうりはなかなかおいしいですね。
This dish is really rather good.
新しい漢字がなかなか覚えられません。
あたらしいかんじがなかなかおぼえられません。
I just can't seem to memorise the new kanji.

Full entry for なかなか

Sentences where only one works

バスがなかなか来ません。
バスがなかなかきません。
The bus just won't come.
なかなか + negative = "not easily, not for ages", with a note of impatience. かなり来ません is not Japanese.
この店はかなり高いです。
このみせはかなりたかいです。
This shop is quite expensive.
A plain statement of degree about an unwelcome quality, so かなり. なかなか高い would sound oddly appreciative of the price.
なかなか上手ですね。
なかなかじょうずですね。
You're pretty good at this, you know.
A compliment with a flavour of pleasant surprise — exactly なかなか's job. かなり上手ですね is a flatter assessment and can sound like grading someone.
予約がなかなか取れませんでした。
よやくがなかなかとれませんでした。
It was really hard to get a reservation.
Difficulty over repeated attempts, so なかなか + negative. To say it plainly you would use かなり難しかった instead.

Common mistakes

バスがかなり来ません。
バスがなかなか来ません。
かなり modifies a degree, and "not coming" has no degree. "It won't come for ages" is a fixed job of なかなか + negative.
先生、なかなかお上手ですね。(said to your teacher)
先生、本当にお上手ですね。
なかなか carries "better than I expected", so it implies you had low expectations. It is fine to a friend or a junior, but it can be rude to a superior.
この本はなかなか難しくないです。
この本はあまり難しくないです。
Learners read なかなか as "quite" and negate it. With a negative, なかなか means "not easily", so the sentence does not mean "not very difficult".

Frequently asked questions

Does なかなか mean "quite" or "not easily"?

Both, and the verb form decides. Affirmative なかなかおいしい is "quite tasty, better than expected". Negative なかなか来ない is "doesn't come for ages, won't come easily".

Is なかなか rude?

Not in itself, but the praise it gives is measured against your own expectations, so aimed upward at a teacher or a boss it can sound condescending. Use 本当に or とても there.

Can I use かなり in writing?

Yes, かなり is neutral and fine in reports and essays. If you want something more formal still, 相当 and 非常に are the written-style alternatives.