なければならない・
Japanese says "must" as "if I don't, it won't do". That makes a long ending, and in conversation it often shrinks to なくちゃ or なきゃ.
a rule
In the library, you must turn off your cell phone.
your own situation
I have an early start tomorrow, so I have to go to bed now.
How to form it
Verb ない-form: ない → なければ／なくては + ならない／いけない
行かない → 行かなければならない, 行かなくてはいけない. Polite なりません, いけません. Past ならなかった, "had to".
Casual
Verb ない-form: ない → なくちゃ／なきゃ
行かなくちゃ, 行かなきゃ.
| Form | Where you'll mostly meet it |
|---|---|
| なければならない, なくてはならない | Rules, notices, writing, careful polite speech |
| なければいけない, なくてはいけない | Everyday speech, plain or polite |
| なくちゃ, なきゃ | Friends, family, talking to yourself |
All six mean the same. なければ and なくては are both "if not"; ならない and いけない are both "it won't do". なくちゃ is short for なくては, and なきゃ for なければ.
Rules, and things you can't get out of
I promised, so I must return the book by tomorrow.
I have to go to city hall and complete the procedure today.
Anyone attending the meeting must arrive by nine.
来る is read こ here, as in 来ない.
There was a lot of work yesterday, so I had to work overtime.
Said straight to someone, it tells them what to do. From a doctor, a teacher or a parent that is natural. To your boss it can sound like an order.
Among friends, and to yourself
なくちゃ and なきゃ often end the sentence, because everyone knows how it finishes. Said like that, it is mostly about yourself: something you just remembered, or why you are leaving. English often says "I've got to" or "I should".
It's already late. I have to go home.
We're out of milk. I have to buy some on the way home.
I should study more.
Are you leaving already?
Yeah. I have to get to the office by nine.
With いけない or the casual だめ put back on, the short forms also ask a question or tell someone else what to do.
Do I have to finish the homework today?
You have to take this medicine every day.
in polite conversation
I have to get up early tomorrow.
Do I have to come tomorrow too?
No, you don't have to.
Asked politely.
The same thing, to two people
I have to be going.
To a teacher or a host. To a friend it sounds like reading out a rule.
The short forms stay out of reports, notices and talk with customers.
It is not "must not"
With two negatives in it, this looks like "must not" to English eyes. It is "must". "Don't have to" and "must not" have endings of their own.
You have to take your shoes off here.
Not taking them off won't do.
You don't have to take your shoes off here.
Not taking them off is fine.
You must not take your shoes off here.
Taking them off won't do.
Close neighbours
ないとN4
"If I don't…", with the rest left unsaid. Very common in conversation.
It's already this late. I have to hurry to the station.
たほうがいいN5
Advice. The other person can still choose; with なければならない there is no choice.
It will rain tomorrow, so you should take an umbrella.
Check yourself
1What does this mean?
明日は
Choose an answer to see why.
2You are texting a friend. Which one fits?
ごめん、
Choose an answer to see why.
More detail
"Must be": でなければならない
A noun or a な-adjective takes でなければ. An い-adjective takes くなければ: 安くなければならない, "it has to be cheap".
In this work, the information must be accurate.
なくてはならない with no verb before it: "can't do without"
Tanaka is someone this team can't do without.
Not "must": if Tanaka weren't there, it wouldn't do.
More sentences
Since it is raining, I have to take an umbrella.
Examinees must show identification.
I have to get up early tomorrow morning.
I have to start getting ready.
To catch the train, I have to run to the station.
I have to make a note so I don't forget.
I have to reply to this email today.