Expressing “must” or “have to”

When there’s something that must or must not be done

In life, there are things that we must or must not do whether it’s taking out the trash or doing our homework. We will cover how to say this in Japanese because it is a useful expression and it also ties in well with the previous section. We will also learn how to the say the expression, “You don’t have to…” to finish off this section.

Using 「だめ」, 「いけない」, and 「ならない」 for things that must not be done


  1. 駄目 【だめ】 – no good
  2. ここ – here
  3. 入る 【はい・る】 (u-verb) – to enter
  4. それ – that
  5. 食べる 【たべ・る】 (ru-verb) – to eat
  6. 夜 【よる】 – evening
  7. 遅い 【おそ・い】 (i-adj) – late
  8. ~まで (particle) – until ~
  9. 電話 【でん・わ】 – phone
  10. する (exception) – to do
  11. 早い 【はや・い】 (i-adj) – fast; early
  12. 寝る 【ね・る】 (ru-verb) – to sleep

If you’re not familiar with the word 「だめ」(駄目), though it can be used in many different ways it essentially means “no good”. The other two key words in this section are 「いけない」 and 「ならない」 and they have essentially the same basic meaning as 「だめ」. However, while 「いけない」 can be used by itself, 「ならない」 must only be used in the grammar presented here. In addition, while 「いけない」 and 「ならない」 conjugate like i-adjectives they are not actual adjectives. Let’s learn how to use these words to express things that must not be done.

How to say: Must not [verb]  

  • Take the te-form of the verb, add the 「は」 (wa) particle and finally attach either 「だめ」、「いけない」、or 「ならない」.
    入る入って + は + だめいけない/ならない = 入ってだめ入っていけない入ってはならない
  1. ここ入っていけません
    You must not enter here.
  2. それ食べてだめ
    You can’t (must not) eat that!
  3. 遅くまで電話してならない。
    You must not use the phone until late at night.
  4. 早く寝てなりませんでした。
    Wasn’t allowed to sleep early.

The difference between 「だめ」、「いけない」、and 「ならない」 is that, first of all, 「だめ」 is casual. While 「いけない」 and 「ならない」 are basically identical, 「ならない」 is generally more for things that apply to more than one person like rules and policies.

Expressing things that must be done


  1. 毎日 【まい・にち】 – everyday
  2. 学校 【がっ・こう】 – school
  3. 行く 【い・く】 (u-verb) – to go
  4. 宿題 【しゅく・だい】 – homework
  5. する (exception) – to do

You may have predicted that the opposite of “You must not do” would use 「いける」 or 「なる」 because they look like the positive version of 「いけない」 and 「ならない」. However, 「いけない」 and 「ならない」 must always be negative, so this is not correct. In actuality, we still use the same 「だめいけない/ならない」 and use the opposite of the verb that goes in front of it instead. This double negative can be kind of confusing at first but you will get used to it with practice. There are three ways to conjugate the verb before adding 「だめいけない/ならない」 and two of them involve conditionals so aren’t you glad that you just learned conditionals in the previous section?

How to say: Must [verb]  

  1. Negative te-form + 「は」 (wa) particle + だめいけない/ならない
  2. Negative verb + 「と」 conditional + だめいけない/ならない
  3. Negative verb + 「ば」 conditional + だめいけない/ならない

The first method is the same as the “must not do” grammar form except that we simply negated the verb.

  1. 毎日学校行かなくてなりません。
    Must go to school everyday.
  2. 宿題しなくていけなかった
    Had to do homework.

The second method uses the natural conditional that we learned in the last lesson. Literally, it means if you don’t do something, then it automatically leads to the fact that it is no good. (In other words, you must do it.) However, people tend to use it for situations beyond the natural consequence characterization that we learned from the last section because it’s shorter and easier to use than the other two types of grammar.

  1. 毎日学校行かないだめです。
    Must go to school everyday.
  2. 宿題しないいけない
    Have to do homework.

The third method is similar to the second except that it uses a different type of conditional as explained in the last lesson. With the 「ば」 conditional, it can be used for a wider range of situations. Note that since the verb is always negative, for the 「ば」 conditional, we will always be removing the last 「い」 and adding 「ければ」.

  1. 毎日学校行かなければいけません
    Must go to school everyday.
  2. 宿題しなければだめだった。
    Had to do homework.

It may seem like I just breezed through a whole lot of material because there are three grammar forms and 「だめいけない/ならない」 adding up to nine possible combinations (3×3). However, some combinations are more common than others but I did not explicitly point out which were more common because any combination is technically correct and going over style would merely confuse at this point. Also, keep in mind that there is nothing essentially new in terms of conjugation rules. We already covered conditionals in the last lesson and adding the wa particle to the te-form in the beginning of this section.

※ Reality Check

Although we spent the last section explaining 「~なければ」 and 「~なくては」, the reality is that because they are so long, they are practically never used in real conversations. While they are often used in a written context, in actual speech, people usually use the 「と」 conditional or the various shortcuts described below. In casual speech, the 「と」 conditional is the most prevalent type of conditional. Though I explained in depth the meaning associated with the 「と」 conditional, you have to take it with a grain of salt here because people are inherently lazy.

Various short-cuts for the lazy


  1. 勉強 【べん・きょう】 – study
  2. する (exception) – to do
  3. ご飯 【ご・はん】 – rice; meal
  4. 食べる 【た・べる】 (ru-verb) – to eat
  5. 学校 【がっ・こう】 – school
  6. 行く 【い・く】 (u-verb) – to go
  7. ここ – here
  8. 入る 【はい・る】 (u-verb) – to enter
  9. 駄目 【だめ】 – no good
  10. 死ぬ 【し・ぬ】 (u-verb) – to die

You may have been grumbling and complaining about how long most of the expressions are just to say you must do something. You can end up with up to eight additional syllables just to say “I have to…”!

Well, others have thought the same before and people usually use short abbreviated versions of 「なくては」 and 「なければ」 in casual speech. Teachers are often reluctant to teach these overly familiar expressions because they are so much easier to use which is bad for times when they might not be appropriate. But, on the other hand, if you don’t learn casual expressions, it makes it difficult to understand your friends (or would-be friends if you only knew how to speak less stiffly!). So here they are but take care to properly practice the longer forms so that you will be able to use them for the appropriate occasions.

Casual abbreviations for things that must be done  

  1. Simply replace 「なくて」 with 「なくちゃ」
  2. Simply replace 「なければ」 with 「なきゃ」

Right now, you may be saying, “What the?” because the “abbreviations” are about the same length as what we’ve already covered. The secret here is that, unlike the expressions we learned so far, you can just leave the 「だめいけない/ならない」 part out altogether!

  1. 勉強なくちゃ
    Gotta study.
  2. ご飯食べなきゃ
    Gotta eat.

The 「と」 conditional is also used by itself to imply 「だめいけない/ならない」.

  • 学校行かない
    Gotta go to school.

There is another 「ちゃ」 abbreviation for things that you must not do. However, in this case, you cannot leave out 「だめいけない/ならない」. Since this is a casual abbreviation, 「だめ」 is used in most cases.

One very important difference for this casual form is that verbs that end in 「む」、「ぶ」、「ぬ」 use 「じゃ」 instead of 「ちゃ」. Essentially, all the verbs that end in 「んだ」 for past tense fall in this category.

Casual abbreviations for things that must not be done  

  1. Replace 「ては」 with 「ちゃ」
  2. Replace 「では」 with 「じゃ」
  1. ここ入っちゃだめだよ。
    You can’t enter here.
  2. 死んじゃだめだよ! – You can’t die!

On a final note, in general, 「ちゃ」 sounds a bit cutesy or girly. You’ve already seen an example of this with the 「ちゃん」 suffix. Similarly, 「なくちゃ」 also sounds a bit cutesy or childish.

Saying something is ok to do or not do


  1. 全部 【ぜん・ぶ】 – everything
  2. 食べる 【た・べる】 (ru-verb) – to eat
  3. いい (i-adj) – good
  4. 飲む 【の・む】 (u-verb) – to drink
  5. 大丈夫 【だい・じょう・ぶ】 (na-adj) – ok
  6. 構う 【かま・う】 (u-verb) – to mind; to be concerned about
  7. もう – already
  8. 帰る 【かえ・る】 (u-verb) – to go home
  9. これ – this
  10. ちょっと – just a little
  11. 見る 【み・る】 (ru-verb) – to see

Now let’s learn how to say either that it’s ok to do or not do something. I decided to shove this section in here because in Japanese, this is essential how to say that you don’t have to something (by saying it’s ok to not do it). The grammar itself is also relatively easy to pick up and makes for a short section.

By simply using the te-form and the 「も」 particle, you are essentially saying, “even if you do X…” Common words that come after this include 「いい」, 「大丈夫」, or 「構わない」. Some examples will come in handy.

  1. 全部食べてもいいよ。
    You can go ahead and eat it all. (lit: Even if you eat it all, it’s good, you know.)
  2. 全部食べなくてもいいよ。
    You don’t have to eat it all. (lit: Even if you don’t eat it all, it’s good, you know.)
  3. 全部飲んでも大丈夫だよ。
    It’s ok if you drink it all. (lit: Even if you drink it all, it’s OK, you know.)
  4. 全部飲んでも構わないよ。
    I don’t mind if you drink it all. (lit: Even if you drink it all, I don’t mind, you know.)

In casual speech, 「~てもいい」 sometimes get shortened to just 「~ていい」 (or 「~でいい」 instead of 「~でもいい」 ).

  1. もう帰っいい
    Can I go home already?
  2. これちょっといい
    Can I take a quick look at this?
Book Navigation<< ConditionalsDesire and Suggestions >>