English has one word, when, that does several different jobs. Norwegian splits one of those jobs in two: da and når both translate as "when" in a time clause, but they are not interchangeable. The dividing line is one that English never draws, so this is the single most frequent time-conjunction error English speakers make. The whole distinction collapses into one test, which you will use again and again:
One single event or period in the PAST → da. Everything else → når.
The core rule
da is for a single, completed event or state in the past — one specific time, that one occasion.
Da jeg kom hjem i går, ringte jeg deg med en gang.
When I got home yesterday, I called you right away.
That happened once, at one identifiable moment. So: da.
når is for everything else — the present, the future, and the repeated/habitual past ("whenever", "every time").
Når jeg kommer hjem, lager jeg alltid en kopp te.
When I get home, I always make a cup of tea.
That is a habit, true on any number of occasions — so når, even though kommer hjem looks just like the past example. The tense of the verb is not the deciding factor; the singularity of the occasion is.
Why the split exists — the logic English hides
English when is blind to a distinction Norwegian considers essential: is this a unique moment or a recurring one? Think of da as pointing a finger at a single coordinate on the timeline — that afternoon, that summer, the moment X happened. når describes a type of moment that can recur — any time the condition is met. Because English collapses both into "when", learners reach for the wrong one without noticing there was even a choice to make. Once you internalise the single-vs-repeated axis, the right word becomes predictable in sentences you have never seen.
This also connects da to its other life as a discourse particle and to the narrative "back then" feeling — see da as a particle and adverb.
da: the single past event
Use da for that one occasion in the past — whether it is a brief event or a whole bounded period treated as a single stretch.
Da han kom inn, ble det stille i rommet.
When he came in, the room went quiet.
Vi bodde i Trondheim da jeg var liten.
We lived in Trondheim when I was little.
That last one surprises English speakers: "when I was little" feels habitual, but it names one continuous childhood period — a single bounded stretch of the past — so it is da jeg var liten. The childhood is one coordinate, not a recurring event.
Det regnet hele dagen da vi var i Bergen.
It rained all day when we were in Bergen.
når: present, future, and repeated past
Present and future
Ring meg når du er ferdig.
Call me when you're done.
Når jeg blir voksen, vil jeg bo ved sjøen.
When I grow up, I want to live by the sea.
Note that Norwegian uses the present tense for the future here (når jeg blir), where English would too — but the conjunction is firmly når because we are talking about the future, never a completed past event.
Repeated / habitual past ("whenever", "every time")
This is the case that trips people up, because the verb is in the past tense yet the conjunction is når — because the event recurred.
Når jeg var liten, dro vi alltid til hytta om sommeren.
When(ever) I was little, we always went to the cabin in the summer.
Compare this with the da version above (da jeg var liten). The difference is the verb in the main clause: dro vi alltid signals a repeated, habitual event — many summers — so the time clause is når. Words like alltid (always), hver gang (every time), and ofte (often) are strong signals you are in repeated territory.
Hver gang han ringte, var jeg opptatt.
Every time he called, I was busy.
Når vi møttes på den tiden, snakket vi alltid om politikk.
Whenever we met back then, we always talked about politics.
A side note: da also means "then"
Outside time clauses, da also means "then" (at that point) and works as a flavouring particle (Kom da! — "Come on, then!"). Those uses are separate from the when-conjunction here; do not let them confuse the rule. The conjunction da = "when, that one past time"; the adverb da = "then". Both exist; this page is about the conjunction.
Decision summary
| Situation | Use | Test phrase | Example |
|---|---|---|---|
| Single completed past event/period | da | "that one time / back then" | Da jeg kom hjem, ... |
| Repeated / habitual past ("whenever") | når | "every time / whenever" | Når jeg var liten, dro vi alltid ... |
| Present | når | "whenever / each time" | Når jeg er trøtt, ... |
| Future | når | "once / as soon as" | Når jeg blir ferdig, ringer jeg. |
The one-line version: one past event/period = *da; everything else = når*.
Common Mistakes
❌ Når jeg kom hjem i går, ringte jeg deg.
Incorrect — a single past event needs da, not når.
✅ Da jeg kom hjem i går, ringte jeg deg.
When I got home yesterday, I called you.
This is the classic error: English "when" pulls the learner toward når for a one-off past event. I går (yesterday) flags a single occasion → da.
❌ Når han døde, var hele familien samlet.
Incorrect — a unique past event must be da.
✅ Da han døde, var hele familien samlet.
When he died, the whole family was gathered.
Some events can only happen once — they are unmistakably da.
❌ Da jeg er ferdig, ringer jeg deg.
Incorrect — da cannot be used for the future; use når.
✅ Når jeg er ferdig, ringer jeg deg.
When I'm done, I'll call you.
da is past-only. Anything present or future is når.
❌ Da jeg var liten, dro vi alltid til hytta.
Borderline/incorrect — the repeated 'always' makes this habitual, so når fits.
✅ Når jeg var liten, dro vi alltid til hytta.
When I was little, we always went to the cabin.
The signal alltid marks a repeated past event → når. (Without alltid, framing the childhood as one period, da jeg var liten would be fine — the meaning shifts with the framing.)
❌ Når jeg så henne for første gang, visste jeg det.
Incorrect — 'the first time' is a single occasion, so da.
✅ Da jeg så henne for første gang, visste jeg det.
When I saw her for the first time, I knew.
For første gang names one specific occasion → da.
Key Takeaways
- da = a single completed event or period in the past ("that one time / back then").
- når = the present, the future, and the repeated/habitual past ("whenever / every time").
- The deciding factor is singularity, not tense: a habitual past still takes når.
- Watch the main clause: alltid, hver gang, ofte signal repetition → når.
- Mnemonic: da = den gang. English "when" hides this split entirely.
Now practice Norwegian
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Start learning Norwegian→Related Topics
- Time Conjunctions: når, da, mens, før, etter atB1 — The temporal subordinators — and the critical når/da split (når for present, future and repeated past; da for a single past event) that has no English equivalent.
- The Particle da: 'Then / Come On'B1 — The spoken-Norwegian modal particle da — how clause-final and medial da adds coaxing, impatience, reassurance, or 'after all', and how it differs from temporal da ('then/when').
- Subordinating Conjunctions: OverviewB1 — The master list of Norwegian subordinating conjunctions and the one rule they all trigger: subordinate word order, where ikke jumps in front of the verb.
- om vs hvis: Whether vs IfB1 — English 'if' splits into two Norwegian words: hvis for a real condition, om for an embedded question — with a one-word test to choose every time.
- Subordinate Clause Word OrderA2 — Inside a subordinate clause Norwegian abandons V2: nothing inverts, the subject stays first, and the sentence adverb — above all ikke — moves to BEFORE the finite verb, the deepest fact in Norwegian word order.