Wann, Wenn, or Als? The German Word for 'When' That English Doesn't Have

English gets away with a single word, “when,” for situations German splits into three completely different words. That mismatch is exactly why wann, wenn, and als trip up learners at every level, not just beginners. The good news is the rule underneath is simpler than it looks once you stop translating from English and start asking one question instead.

What’s the difference between wann, wenn, and als in German?

Use wann for questions, wenn for repeated or general situations (and any future situation), and als for a single completed event in the past. That’s the entire rule. Everything else in this guide is just applying it to the situations where English’s single “when” makes people second-guess themselves.

When do you use “wann”?

Wann is used only for questions, direct or indirect, about time. If you can imagine a question mark at the end of the sentence, or if the sentence is really asking “at what time,” wann is almost certainly correct.

“Wann kommst du?” (When are you coming?) is a direct question. “Ich weiß nicht, wann er ankommt” (I don’t know when he’s arriving) is an indirect question — it still functions as a question about time even though it’s embedded in a statement.

The test that trips people up least: if you could rephrase the sentence in English as “at what time,” wann is right.

When do you use “wenn”?

Wenn covers two situations: anything repeated or habitual in any time frame, and anything in the future, no matter how many times it happens. This is the word English speakers most often use incorrectly, because English uses “when” for both repeated past events and single past events, and German doesn’t.

For repeated situations, “Wenn ich müde bin, trinke ich Kaffee” (When I’m tired, I drink coffee) describes a general pattern, not one specific instance. For the future, “Wenn ich morgen ankomme, rufe ich dich an” (When I arrive tomorrow, I’ll call you) uses wenn even though it’s a single event, because it hasn’t happened yet.

Wenn also covers conditional “if” in German, which is part of why it shows up so often. “Wenn es regnet, bleibe ich zu Hause” (If it rains, I’ll stay home) uses the same word as the temporal wenn, since German treats habitual and conditional “when/if” as functionally related.

When do you use “als”?

Als is used only for a single, completed event in the past — one specific occurrence, not a pattern. This is the word that most directly conflicts with English habits, because English happily reuses “when” here too.

“Als ich ein Kind war, wohnte ich in Berlin” (When I was a child, I lived in Berlin) refers to one continuous, non-repeating period. “Als ich ihn gestern sah, hat er gelacht” (When I saw him yesterday, he laughed) refers to one specific past moment. Compare that to “wenn ich ihn sehe, lacht er immer” (when I see him, he always laughs) — same verb, same general topic, but wenn is correct because it’s describing a repeated pattern rather than one occasion.

Why does English collapse all three into “when”?

English simply never grammaticalized this distinction the way German did. English relies on context and extra words (usually, every time, once, back then) to signal what German signals directly through word choice. This is precisely why direct translation fails here: English speakers aren’t missing a grammar rule so much as translating past a distinction their own language never asks them to make.

What’s a quick way to decide between wann, wenn, and als?

Ask three questions in order, and the first one that fits gives you the answer.

1. Is it a question about time, direct or indirect? If yes, use wann.
2. Is it in the future, or does it happen more than once (in any time frame)? If yes, use wenn.
3. Is it one specific, completed event in the past? If yes, use als.

This order matters because als only applies once you’ve already ruled out repetition. A past event that happened many times is still wenn, not als, even though it’s in the past.

Common mistakes with wann, wenn, and als

The most frequent mistake is using als for any past-tense sentence, without checking whether it was a single event or a repeated one. “Als ich jung war, spielte ich Fußball” is correct for a general childhood period, but “wenn ich Fußball spielte, war ich glücklich” needs wenn if it’s describing a repeated feeling across many instances of playing, not one game.

A second common mistake is using wenn for direct questions, carried over from how naturally “when” opens a question in English. “Wenn kommst du?” is incorrect — it needs to be “wann kommst du?” since it’s a direct question, not a conditional or repeated situation.

A third mistake is forgetting that wenn does double duty as “if.” Learners sometimes hunt for a separate word for conditional sentences and miss that wenn already covers it, which actually simplifies things once you know to expect it.

Frequently asked questions

Can wenn ever refer to the past?

Yes, wenn refers to the past when the situation was repeated or habitual. A single past event uses als instead, even though both translate to “when” in English.

Is als only used for childhood memories?

No, als applies to any single, completed past event, not just childhood. It’s just especially common in stories about childhood because those often describe one continuous period rather than a repeated pattern.

Does wann ever appear outside of questions?

No, wann is reserved for questions, whether asked directly or embedded inside another sentence as an indirect question.

If this kind of distinction is the sort of thing that keeps tripping you up mid-conversation, that’s exactly the gap a few targeted 1-on-1 lessons close faster than more solo study, since it’s really a pattern-recognition skill that’s easier to build with live correction than by memorizing the rule alone.