Japanese grammar
What does ～べきだ mean? Japanese grammar N4
～べきだ means should ~ (moral obligation, duty).
| Level (estimated, JLPT framework) | N4 |
|---|---|
| Structure | V (dictionary form) + べきだ V (dictionary form) + べきではない (should not) V (dictionary form) + べきだった (should have) |
| Romaji | ~ beki da |
| Meaning | should ~ (moral obligation, duty) |
Forming it
| Negative | ～べきではない／～べきじゃない |
|---|---|
| Regular verb | 言う → 言うべきだ, 守る → 守るべきだ |
| Past (regret) | ～べきだった (should have done but didn't) |
| する (exception) | する → するべきだ OR すべきだ (both correct) |
How to use it
States that something is right, morally proper, and should be done.
- べきだ differs from ～方がいい in what the advice is BASED ON. ～方がいい is based on practical benefit ("doing that is good for you"); べきだ is based on right and wrong, morality, responsibility ("doing that is the correct thing"). That's why べきだ sounds serious and judgmental.
- Because it's judgmental, this pattern is fairly strong — using it with a superior is very rude, and using it often with friends can also sound preachy. It suits opinions about society, rules, and ethics more than everyday personal advice.
- べきだった is a very useful form: it expresses regret about something that should have been done but wasn't — もっと早く言うべきだった (I should have said it sooner).
- べきではない = "should not" in the moral sense, stronger than ～ない方がいい but weaker than ～てはいけない (an outright prohibition).
Examples
約束したなら、守るべきです。
If you made a promise, you should keep it.
子どもにそんなことを言うべきではありません。
You should not say such things to a child.
もっと早く先生に相談するべきでした。
I should have consulted my teacher earlier.
Keep in mind
- する has two forms: するべきだ (common in spoken language) and すべきだ (more classical, common in writing/journalism). Both are accepted.
- べきだ is NOT used with ある or verbs describing a natural state — it requires an action that can be chosen.
Common mistakes
-
Wrong風邪ですね。薬を飲むべきですよ。
You have a cold. You should take medicine.
Correct風邪ですね。薬を飲んだ方がいいですよ。
Personal health matters are practical advice, not a moral issue — using ～方がいい sounds far more natural.
-
Wrong部長はもっと休むべきです。
The department manager should rest more.
Correct部長、もっとお休みになった方がよろしいのではないでしょうか。
べきだ is judgmental; saying it directly to a superior is a serious breach of etiquette.
-
Wrong明日は晴れるべきだ。
It'll probably be sunny tomorrow.
Correct明日は晴れるはずだ。
A natural occurrence/inference uses 「はずだ」; 「べきだ」 is only used for what should be done according to what is right.
-
Wrongたばこを吸うべきだ。
One should not smoke.
Correctたばこを吸うべきではない。
"Should not (smoke)" uses 「～べきではない」.
Exam tips
- Distinguish the 3 patterns: ～方がいい (benefit) / ～べきだ (morality) / ～なければならない (obligation, no choice).