German has roughly a dozen temporal conjunctions where English makes do with a handful, and English "when" alone splits into three German words. The trap is not understanding what each conjunction means — it is that several of them force a particular tense in the clause they introduce. Choosing the conjunction is therefore not the last decision; it is the first, because the conjunction dictates the tense sequence. This page is built as a series of decision scenarios. All of these conjunctions are subordinating: they send the verb to the end and are preceded by a comma.
The big split: als vs wenn vs wann
English "when" does three different jobs that German keeps strictly separate.
| Word | Use | Tense / context |
|---|---|---|
| als | a single, completed event in the past | past (Präteritum / Perfekt) |
| wenn | repeated events ('whenever'), or present/future 'when/if' | any tense except a one-off past |
| wann | a question word ('at what time'), direct or indirect | question, not a statement-joiner |
The clean test: one past event → als; everything else → wenn; a question → wann.
Als ich gestern nach Hause kam, war niemand da.
When I got home yesterday, nobody was there.
Immer wenn es regnete, blieben wir drinnen.
Whenever it rained, we stayed inside.
Ich weiß nicht, wann der Zug abfährt.
I don't know when the train leaves.
nachdem and the obligatory tense step-down
This is the conjunction that trips up almost everyone. Nachdem (after) describes an event that finished before the main clause begins, so German marks that earlier event with an earlier tense. The two valid pairings are:
| nachdem-clause | Main clause | Used for |
|---|---|---|
| Plusquamperfekt (had done) | Präteritum (did) | past narration (written, formal) |
| Perfekt (have done) | Präsens (do) | present / spoken, habitual |
Nachdem wir gegessen hatten, gingen wir spazieren.
After we had eaten, we went for a walk.
Nachdem ich geduscht habe, trinke ich immer einen Kaffee.
After I have showered, I always drink a coffee.
You may not put both clauses in the same simple tense the way English does ("after we ate, we went"). German insists on the step-down because nachdem is purely about sequence — the conjunction itself signals "this happened first," and the anterior tense reinforces it.
while: während
Während marks two things happening at the same time. Both clauses normally share the same tense, since they are simultaneous. (Während can also mean "whereas" in a contrastive sense, but here we use it temporally.)
Während du kochst, decke ich schon mal den Tisch.
While you cook, I'll set the table in the meantime.
Während wir auf den Bus warteten, fing es an zu schneien.
While we were waiting for the bus, it started to snow.
before and as soon as: bevor / ehe and sobald
Bevor (before) and its more formal twin ehe mark an event that comes after the main clause. Tenses usually match — no step-down needed, because the main clause is the earlier event.
Bevor du gehst, schalte bitte das Licht aus.
Before you leave, please turn off the light.
Sobald (as soon as) marks an event that triggers the main clause immediately afterwards — common with the future.
Sobald ich zu Hause bin, rufe ich dich an.
As soon as I'm home, I'll call you.
since, until, as long as: seit(dem), bis, solange
Seit(dem) (since) marks the starting point of something still going on. The crucial point: for an ongoing situation German uses the present tense where English uses the present perfect.
Seitdem ich in Berlin wohne, fahre ich nur noch Fahrrad.
Since I have been living in Berlin, I only ride a bike.
Bis (until) marks an end point; solange (as long as) marks a span during which something holds.
Warte bitte hier, bis ich zurückkomme.
Please wait here until I come back.
Solange du bei mir wohnst, gelten meine Regeln.
As long as you live with me, my rules apply.
Decision practice
Read each situation, then check the conjunction and the tense it forces.
1. A one-time past event: "The phone rang at the exact moment I walked in the door."
Genau als ich zur Tür hereinkam, klingelte das Telefon.
Right when I came in the door, the phone rang.
2. A repeated childhood habit: "Whenever we visited Grandma, she baked a cake."
Immer wenn wir Oma besuchten, backte sie einen Kuchen.
Whenever we visited Grandma, she baked a cake.
3. Sequence in the past: "After he had passed the exam, he celebrated all night."
Nachdem er die Prüfung bestanden hatte, feierte er die ganze Nacht.
After he had passed the exam, he celebrated all night.
4. Ongoing since a start point: "Since I quit smoking, I feel much better."
Seit ich mit dem Rauchen aufgehört habe, fühle ich mich viel besser.
Since I quit smoking, I feel much better.
Why English speakers go wrong here
English smooths over distinctions German keeps sharp. "When" covers als, wenn and wann, so the default English instinct — reach for wenn every time — produces wrong past sentences. And English "after" needs no tense shift: "after we ate, we left" keeps both verbs simple. Transferring that straight into German (nachdem wir aßen, gingen wir) is the single most common mistake at this level. German treats the conjunction and the tense as a package; you cannot pick one without the other.
Common Mistakes
❌ Wenn ich gestern nach Hause kam, war niemand da.
Incorrect — a single past event needs als, not wenn.
✅ Als ich gestern nach Hause kam, war niemand da.
When I got home yesterday, nobody was there.
❌ Nachdem wir aßen, gingen wir spazieren.
Incorrect — nachdem requires the tense step-down (Plusquamperfekt then Präteritum).
✅ Nachdem wir gegessen hatten, gingen wir spazieren.
After we had eaten, we went for a walk.
❌ Ich weiß nicht, als der Zug abfährt.
Incorrect — an indirect question needs the question word wann, not als.
✅ Ich weiß nicht, wann der Zug abfährt.
I don't know when the train leaves.
❌ Seitdem ich in Berlin gewohnt habe, fahre ich Fahrrad.
Incorrect — an ongoing situation after seit takes the present tense in German.
✅ Seitdem ich in Berlin wohne, fahre ich Fahrrad.
Since I have been living in Berlin, I ride a bike.
Key Takeaways
- Past 'when': single event → als; repeated → wenn; a question → wann.
- nachdem forces an anterior tense: Plusquamperfekt + Präteritum, or Perfekt + Präsens. Never same-tense it.
- seit(dem) with an ongoing situation takes the present tense in German.
- während (simultaneous), bevor / ehe (earlier main clause), sobald (immediate trigger), bis (end point), solange (span) generally keep matching tenses.
- All of these are subordinating: comma + verb to the end.
Now practice German
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Start learning German→Related Topics
- Temporal Conjunctions: als, wenn, während, bevor, nachdem, bis, seitB1 — The time conjunctions all send the verb to the end, but each marks a precise relationship — and the als/wenn split for the past is one of the top intermediate errors.
- The Plusquamperfekt (Past Perfect)B1 — How to form and use the Plusquamperfekt — the Präteritum of haben or sein plus a participle — for an action completed before another past action.
- Verb-Final Order in Subordinate ClausesB1 — Why a subordinating conjunction sends the finite verb to the very end of the clause — and why in compound tenses the auxiliary lands dead last.
- wann and Time QuestionsA2 — wann asks 'when' — but only in questions. Learn the family of time questions (seit wann, bis wann, wie lange, wie oft) and why wann must never be used as the conjunction 'when' in a statement.
- Subordinating Conjunctions: OverviewB1 — Every subordinating conjunction — dass, weil, wenn, obwohl, damit and the rest — does the same thing: it sends the finite verb to the end of its clause. Learn the list, and the syntax becomes automatic.