Introduction to als, wenn & wann

All three words translate as "when" in English — but they are never interchangeable. Each one covers a distinct grammatical and temporal situation, and mixing them up is one of the most reliable markers of a non-native speaker. The good news is that the distinction follows a clear logic: wann asks questions, als tells a story about a single moment in the past, and wenn handles everything else. A simple decision tree is all you need.

Why als, wenn & wann Matter

All three translate as "when" — English gives you no guidance: The sentence "when I was young" maps to als in German. "When I arrive, call me" maps to wenn. "Do you know when the film starts?" maps to wann. The same English word, three different German words.
Using the wrong one is immediately noticeable: A native speaker hears the wrong choice instantly. Wann ich jung war does not exist. Als ich anrufe, bin ich zu Hause says something happened once in the past — not what was intended.
The word order rule applies to all three: All three introduce subordinate clauses — the verb goes to the end. This does not change across the three words.
als has a time-only meaning here: Als used as a conjunction meaning "when" (single past event) is completely different from als used in comparisons (größer als). Both exist and both are common — learners need to keep them separate.

Understanding als, wenn & wann

The Decision Tree

The fastest way to choose is to ask three questions in order:

Question	If yes → use
Is "when" a question word (direct or indirect)?	wann
Does "when" refer to a single, one-time event in the past?	als
Everything else — present, future, conditional, repeated past?	wenn

wann — Question Word Only

Wann is exclusively a question word. It appears in direct questions and in indirect questions (embedded questions inside a statement). It never introduces a time clause that describes when an action occurred — that is the job of als or wenn:

Type	Example	English
Direct question	Wann fängt der Film an?	When does the film start?
Direct question	Wann bist du geboren?	When were you born?
Indirect question (after wissen)	Ich weiß nicht, wann er kommt.	I don't know when he is coming.
Indirect question (after fragen)	Sie fragt, wann das Konzert endet.	She is asking when the concert ends.
Indirect question (after sagen)	Kannst du mir sagen, wann der Zug abfährt?	Can you tell me when the train departs?

Key test for wann: Can you replace "when" with "at what time"? If yes → wann.

als — A Single Event in the Past

Als refers to a specific, single, completed event or period in the past — something that happened once. It is used with simple past (Präteritum) or present perfect (Perfekt) to describe a moment or stretch of time that will not repeat:

Type	Example	English
Single moment in past	Als ich aufwachte, schien die Sonne.	When I woke up, the sun was shining.
Childhood / specific life period	Als ich Kind war, wohnte ich in Hamburg.	When I was a child, I lived in Hamburg.
Single completed event	Als er ankam, hatten wir schon gegessen.	When he arrived, we had already eaten.
First time something happened	Als ich zum ersten Mal flog, hatte ich Angst.	When I flew for the first time, I was afraid.

Key test for als: Did this happen exactly once, at a specific point or period in the past that cannot be repeated? If yes → als.

wenn — Present, Future, Conditional, Repeated Past

Wenn covers all temporal situations that als and wann do not. This includes present and future time clauses, conditional sentences ("if/when"), and repeated or habitual past actions:

Type	Example	English
Present time clause	Wenn ich Zeit habe, lese ich.	When(ever) I have time, I read.
Future time clause	Wenn du ankommst, ruf mich an.	When you arrive, call me.
Conditional ("if")	Wenn es regnet, bleibe ich zu Hause.	If / when it rains, I stay home.
Repeated past action	Wenn wir früher Urlaub machten, fuhren wir ans Meer.	Whenever we went on holiday, we went to the sea.
Repeated past with immer	Immer wenn er lachte, musste ich auch lachen.	Every time he laughed, I had to laugh too.

Key test for wenn: Is this happening now, in the future, conditionally, or more than once in the past? If yes → wenn.

The Critical Difference: als vs. wenn in the Past

This is where learners make the most errors. Both als and wenn can refer to the past — the distinction is whether the event happened once or repeatedly:

With als — single past event	With wenn — repeated past event
Als ich das erste Mal Ski fuhr, fiel ich hin.	Wenn wir Ski fuhren, hatten wir immer viel Spaß.
The first time — happened once	Whenever we went — happened repeatedly
Als er gestern ankam, regnete es.	Wenn er ankam, brachte er immer Blumen mit.
Yesterday — one specific occasion	Every time he arrived — a repeated pattern
Als wir Kinder waren...	Wenn wir Kinder waren, spielten wir immer draußen.
That period of childhood — once in total	Every time we were children (habitual behaviour during that period)

Word Order — All Three Send the Verb to the End

All three words introduce subordinate clauses. In every case, the conjugated verb moves to the final position in the clause:

Conjunction	Example	Verb at end
wann	Ich weiß nicht, wann er kommt.	kommt — at end ✓
als	Als ich jung war, lebte ich in Berlin.	war — at end ✓
wenn	Wenn du fertig bist, sag mir Bescheid.	bist — at end ✓

When the subordinate clause comes first (as in the last two examples above), the main clause begins with the verb: Als ich jung war, lebte ich in Berlin. The main clause verb immediately follows the comma.

Step-by-Step Decision Guide

Is "when" asking a question — directly or indirectly after verbs like wissen, fragen, sagen? → wann.
Is the event in the past AND did it happen only once? → als.
Is the event in the past AND did it happen repeatedly or habitually? → wenn.
Is the event in the present or future? → wenn.
Is "when" acting as "if" (conditional)? → wenn.

Pro Tip: A reliable shortcut for the als/wenn decision — if you can add "for the first time" or name a specific year or date, it is almost certainly als. If you can add "every time" or "whenever," it is wenn.

Memory Pattern: Think of als as a photograph — one specific moment, captured once. Think of wenn as a video on loop — an action that plays over and over, or could happen in the future. Think of wann as a clock — you are pointing at it and asking what time.

Key Examples

German	English	Note
Wann fängt die Vorlesung an?	When does the lecture start?	wann — direct question about time
Ich weiß nicht, wann er zurückkommt.	I don't know when he is coming back.	wann — indirect question after wissen
Als ich Kind war, liebte ich das Meer.	When I was a child, I loved the sea.	als — single past period (childhood happens only once)
Als sie ankam, warteten wir schon.	When she arrived, we were already waiting.	als — single completed past event
Wenn ich Zeit habe, gehe ich laufen.	When(ever) I have time, I go for a run.	wenn — present, habitual action
Wenn du nach Hause kommst, essen wir.	When you come home, we will eat.	wenn — future time clause
Wenn es regnete, blieben wir drinnen.	Whenever it rained, we stayed inside.	wenn — repeated past, habitual behaviour
Als er zum ersten Mal flog, war er nervös.	When he flew for the first time, he was nervous.	als — "for the first time" signals a single event
Immer wenn sie sich stritten, wurde er ruhiger.	Every time they argued, he became quieter.	wenn — immer wenn = every time, repeated
Kannst du mir sagen, wann die Bibliothek schließt?	Can you tell me when the library closes?	wann — indirect question after sagen

Common Mistakes

Mistake 1: Wann ich jung war, wohnte ich in Wien.
- Fix: Wann is a question word only — it cannot introduce a time clause describing when something happened. A single past event uses als: Als ich jung war, wohnte ich in Wien.
Mistake 2: Als ich nach Hause komme, rufe ich dich an.
- Fix: Future time clauses use wenn, not als. Als is past only: Wenn ich nach Hause komme, rufe ich dich an.
Mistake 3: Ich frage mich, als er ankommt.
- Fix: Als cannot introduce an indirect question. Use wann after question-embedding verbs: Ich frage mich, wann er ankommt.
Mistake 4: Als wir Urlaub machten, gingen wir immer ans Meer.
- Fix: The word immer (always/every time) signals a repeated past action — use wenn: Wenn wir Urlaub machten, gingen wir immer ans Meer. Als would mean a single specific holiday, not a recurring pattern.
Nuance 1: Wenn meaning "if" vs. "when."
- Fix: In German, wenn covers both "when" (temporal) and "if" (conditional). Context and tense make the meaning clear: Wenn es regnet, bleibe ich zu Hause can mean "if it rains" or "when(ever) it rains" — both are correct readings and both use wenn. There is no separate word for conditional "if" at the B1 level (Konjunktiv II handles hypotheticals).

Cultural Insights

als in storytelling: Als is the natural conjunction for telling personal stories and anecdotes in German. Als ich damals in Berlin lebte..., Als wir uns zum ersten Mal begegneten... — these openings are the standard way to frame a memory or narrative. Mastering als is essential for telling stories naturally in German.
immer wenn — a fixed expression of recurrence: The combination immer wenn (every time that, whenever) is extremely common in spoken German and signals a habitual past or present pattern. Immer wenn ich ihn sehe, muss ich lachen. It is both grammatically reliable and stylistically natural — worth learning as a fixed phrase alongside the rule.

Practice Scenarios

Telling childhood memories: Using als for single past periods, e.g., Als ich klein war, wohnte ich auf dem Land — aber wenn wir in die Stadt fuhren, war das immer aufregend. (When I was small, I lived in the countryside — but whenever we went to the city, it was always exciting.)
- Als ich Kind war... (When I was a child...)
- Als ich zum ersten Mal... (When I first...)
- Wenn wir früher... (Whenever we used to...)
Making future plans: Using wenn for future conditions, e.g., Wenn du fertig bist, können wir gehen — sag mir wann, damit ich bereit bin. (When you are ready, we can go — tell me when, so I am prepared.)
- Wenn ich... (bin / habe / komme)... (When I am / have / come...)
- Kannst du mir sagen, wann...? (Can you tell me when...?)
Describing habits and patterns: Using wenn for recurring events, e.g., Immer wenn es schneit, freue ich mich wie ein Kind. (Every time it snows, I feel as happy as a child.)
- Immer wenn... (Every time...)
- Wenn ich müde bin... (When I am tired...)
- Jedes Mal wenn... (Every time...)

Follow-Up Questions

Can als ever refer to the present or future?
- Example Answer: No — als as a temporal conjunction is strictly past tense. It refers to a single completed event or period in the past. For present or future time clauses, wenn is always used. Als does appear in comparisons (größer als = bigger than) but that is a completely different grammatical function.
How do you choose between als and wenn for a past event?
- Example Answer: Ask whether the event happened once or repeatedly. Als ich jung war — childhood is a single unrepeatable period — als. Wenn wir jung waren und draußen spielten — a habitual activity during that period — wenn. If you can add immer or jedes Mal, it is wenn. If you can specify it was the first or only time, it is als.
Is wann always a question word? Can it ever mean "when" in a time clause?
- Example Answer: Wann is exclusively a question word — direct or indirect. It never introduces a time clause describing when an action occurred. Ich weiß nicht, wann er kommt is an indirect question (asking about time). Als er kam, war ich froh describes when something happened — that requires als, not wann.

Conclusion

The three-way distinction between wann, als, and wenn is one of the most important things to get right at B1 level — and the logic is simple once stated clearly. Wann asks about time. Als tells a single past story. Wenn describes everything recurring, present, future, or conditional. Apply the decision tree to any new sentence and the right word becomes obvious.

Practice Makes Perfect

The exercises focus especially on the als vs. wenn distinction in the past — the most error-prone choice — as well as the indirect question use of wann, which learners frequently confuse with als.