word choice - In a period of time

What's the best way to express in in the following sentence:

I will go in five minutes time.

Here's my attempt　　　　

五分かいあとで行きます。

Here's another attempt which I have even less confidence in:

いまから五分行きます

Assuming the above are correct then I would translate them as "I will go after 5 minutes", and "I will go 5 minutes from now". So, questions:

1. Are the above correct?


2. If not then please explain what I've done wrong.


3. Are there better ways to say it?

Please excuse the inconsistent kanji. I've only used the kanji I already know.

Thanks

Answer

The easiest and most commonly-used structure for expressing:

"come/go/return, etc. + in + (time period) " would be to use particle 「で」 and say:

「(time period) + で + [来]{き}ます/[行]{い}きます/[戻]{もど}ります, etc.」

This would by far be the most versatile way of expressing "in (a time period)"

Other expressions:

「(time period) + [後]{ご}に + (verb phrase)」

This expression is less versatile than the one using 「で」 because it cannot be used to make a general statement such as "Instant ramen cooks in 3 minutes."

「インスタントラーメンは3分でできる。」 can be said anytime as a general statement because it is "true".

「インスタントラーメンは3分後にできる。」, however, can only be said when you are actually starting to cook instant ramen.

I have seen quite a few Japanese-learners make mistakes in using these two expressions correctly.

You can also choose to place 「あと」 in front of the time period and say:

「あと５分で行きます。」