Duration with "i"
When you want to express how long an ongoing action lasts—like practicing an instrument or recording in a studio—Danish uses the preposition i. This translates to "for" in English when talking about a duration of time.
| The orchestra practices for two hours. | Orkestret øver i to timer. |
| The choir practices for four hours today. | Koret øver i fire timer i dag. |
Future Time with "om"
To talk about an event that will happen at a specific point in the future—meaning "in [amount of time] from now"—Danish uses the preposition om.
| The audience arrives in an hour. | Publikummet ankommer om en time. |
| His choir sings in the church in a week. | Hans kor synger i kirken om en uge. |
Contrasting "i" and "om"
It is easy to mix these two up, but remember this simple rule: use i for the length of an activity (how long it lasts), and om for the countdown until an activity happens (when it starts).
Let's look at similar situations using both prepositions. Notice how i describes the duration of playing, while om tells us when the playing will begin.
| The father plays the guitar for an hour. | Faren spiller på guitaren i en time. |
| The mother is going to play the guitar in ten minutes. | Moren skal spille på guitaren om ti minutter. |
You will frequently use both prepositions together when discussing schedules and planning upcoming events, like music tours or festivals.
| The tour begins in two weeks, and we play for a month. | Turneen begynder om to uger, og vi spiller i en måned. |
