What is the difference in nuance between しなきゃ and しないと


Obviously, なきゃ is the short/casual form of なければならない like in: 病院へ行かなきゃ。 I need
to go to the hospital.

But I've also seen negative + と be used to express the same thing. 病院へ行かないと。

I assume と here is conditional but is a difference in nuance between the two?
Or are they both interchangeable?




Simply, ～しなきゃ is more informal. It is usually wise to avoid しなきゃ unless you're
talking with your friends (although this depends on your age and personality).
～しないと is not particularly formal, but it's polite enough when you are
conversing with a stranger or your boss.

More generally, the [eba-to-ya
contraction](https://japanese.stackexchange.com/a/12580/5010) is considered
highly colloquial or informal.




Simply, ～しなきゃ is more informal. It is usually wise to avoid しなきゃ unless you're
talking with your friends (although this depends on your age and personality).
～しないと is not particularly formal, but it's polite enough when you are
conversing with a stranger or your boss.

More generally, the [eba-to-ya
contraction](https://japanese.stackexchange.com/a/12580/5010) is considered
highly colloquial or informal.

