in einer Woche or nach einer Woche?
b1Both measure the same week, but from different points: in counts forward from the moment of speaking, nach counts from another event. That is why in is nearly always future and nach nearly always relative.
in
Counted from now: in einer Woche means seven days from today. Dative, usually with the present tense for the future.
In einer Woche fange ich an.I am starting in a week.
nach
Counted from a named event: nach dem Kurs, nach einer Woche Urlaub. Dative, and it works in any tense.
Nach einer Woche hatte er sich eingelebt.After a week he had settled in.
The mistake
Nach zwei Tagen rufe ich dich an - gemeint sind zwei Tage ab heute.
In zwei Tagen rufe ich dich an.
With no event named, nach has no reference point and the sentence leaves open what is being counted from. Counting from now takes in.
Rule of thumb
Is there an event in the sentence to count from? Then nach. Otherwise the reference point is the moment of speaking, and that means in.
Learn this with merke.me
Create a free account to practice this with spaced repetition and track your progress.
Start free