How to Say “I Have to” in Japanese

Let's say you've studied Japanese for a while. In your textbook, you probably learned "I have to" is:

～なければなりません

This is a combination of なければ which means "if (one) doesn't..." and なりません which means "must not." The double negative means, "one must do."

But how often have you heard なければなりません in the wild? Probably not from your friends, but perhaps you've heard it on news broadcasts or with speeches and more formal occasions.

It is a little stiff. Just like the panda below...

So, how do Japanese people really say "I have to" normally?

We'll get to that, but first, here's another form of the stiff なければなりません: なければいけません. 

Both mean "have to; must; should; ought to" but there is a (very) subtle difference in the なりません and いけません.

• なりません sounds final and formal. It is objectively understood you should not do something. "You must not do something." 
• いけません is more subjective and perhaps slightly less formal. "You should not to do something"

So, なりません may be slightly stronger, but in general, these two are totally interchangeable. 

In this article, we'll use いけない or いけません for the examples, but ならない or なりません are also possible.

Construction:

The good news is, all the forms (except the last one--which is even easier) use the following construction.

• Get the ない form of a verb
• Drop the ない
• Add one of the forms below

Ready for the real Japanese you might hear in the wild? Let's get to it.

Less Stiff (Casual) Forms

なきゃ (+ いけない (or ならない)) [Used by males and females]

• 行(い)かなきゃいけない I have to go.

or shorten further:

• 行いかなきゃ I gotta go.

• 勉強(べんきょう)しなきゃ I gotta study.

People often say ～なきゃ when talking to themselves.

あ、行いかなきゃ！

However, if you want to add something after the verb, you need to bring back the いけない. This isn't always done in very casual conversation, but to be correct, bring back いけない. For example:

なくちゃ  + いけない (or ならない) [Used by males and females]

• 行いかなくちゃいけない I have to go.

As with なきゃ, it is usually said without the いけない unless there is some word after the verb.

• 行いかなくちゃ I gotta go.

• 勉強べんきょうしなくちゃ I gotta study.

ないと  + いけない (or ならない)

• 行いかないといけない I have to go.

With this form, don't drop the ない! Just add と and いけない after it. Easy.

As with the above examples, you can also drop the いけない:

• 行いかないと I gotta go. 

This form, however, can be used in formal situations by adding いけません (the ます form):

The formal ないといけません is probably more common and definitely easier to say than the textbook なければいけません. You keep the ない and just add と.

In conclusion

• For formal usage, just use ～ないといけません
• For casual usage, use なきゃ or なくちゃ