English has one word, when, for three different jobs: telling a story about a past moment ("when I was little…"), describing a recurring or future situation ("when it rains…"), and asking a question ("when are you coming?"). Dutch splits these across three separate words — toen, als, and wanneer — and the line between them is sharp and tense-driven. Pick the wrong one and the sentence doesn't just sound off; it can mean something different. The single most important fact, the one English speakers must over-learn, is that a single, completed event in the past can only be toen — never als, even though English happily says "when" there.
The one rule
Three questions, answered in order, pick the word:
- Is it a single event in the past? → toen.
- Is it repeated/habitual, or present/future (or a condition, "if")? → als.
- Is it a question ("when?"), or a time that is unknown/uncertain ("I don't know when…")? → wanneer.
All three are subordinating: the verb goes to the end of their clause.
Toen ik klein was, woonden we in Groningen.
When I was little, we lived in Groningen. — one stretch of past, so toen.
Als ik moe ben, ga ik altijd vroeg naar bed.
When(ever) I'm tired, I always go to bed early. — a recurring present habit, so als.
Toen: a single event in the past
Toen is reserved for the past, and specifically for a single, one-off point or stretch of past time. If you're narrating something that happened once — "when I arrived," "when she called," "when I was a student" — it's toen. This is the word English speakers most often get wrong, because English uses "when" here without blinking.
Toen hij binnenkwam, werd het meteen stil.
When he came in, it instantly went quiet. — a single past moment: toen.
Toen we in Italië waren, hebben we elke dag pasta gegeten.
When we were in Italy, we ate pasta every day. — one past trip (a single occasion), so toen.
Ik was net de deur uit toen de telefoon ging.
I'd just left when the phone rang. — one past event: toen, even mid-sentence.
Note that last example: even when the eating repeated daily, the occasion (being in Italy) was a single past stretch, so toen is correct. The test is the framing event, not whether sub-actions repeat.
Als: habitual, present, future — and 'if'
Als covers everything that isn't a single past event: actions that repeat ("whenever"), and anything in the present or future. Crucially, als also means if — and Dutch makes no distinction between conditional "if" and habitual "whenever," because both describe situations that may or may not hold rather than a fixed past fact.
Als het regent, neem ik de bus.
When/whenever it rains, I take the bus. — a recurring situation: als.
Bel me even als je klaar bent.
Just call me when you're done. — future, so als.
Vroeger, als we bij oma logeerden, kregen we altijd pannenkoeken.
In the old days, when(ever) we stayed at grandma's, we always got pancakes. — repeated past habit, so als (not toen!).
That third example is the subtle one. It's in the past, yet it takes als, because the event was habitual ("every time we stayed"), not a single occasion. The toen/als line in the past is exactly once (toen) vs. repeatedly (als).
Als ik later groot ben, word ik piloot.
When I'm grown up, I'll be a pilot. — future, so als.
Wanneer: questions and unknown times
Wanneer is the question word "when?" — both in direct questions and in embedded ones where the time is unknown or uncertain. If there's a question mark, or an "I don't know / it's unclear" flavour, reach for wanneer.
Wanneer kom je eindelijk eens langs?
When are you finally going to come by? — a direct question: wanneer.
Ik weet niet wanneer de trein vertrekt.
I don't know when the train leaves. — embedded, time unknown: wanneer.
Het is nog onduidelijk wanneer de uitslag komt.
It's still unclear when the result will come. — uncertain time, so wanneer.
A note on register: in everyday speech, Dutch often replaces a plain statement "when" with als, not wanneer. Wanneer in a flat, non-question statement ("I'll come wanneer it's ready") sounds stiff or formal. So don't reach for wanneer just because English used "when" — only for genuine questions and unknown times.
Side by side
| Situation | Word | Example |
|---|---|---|
| single event, past | toen | Toen ik klein was… |
| repeated / habitual (any tense) | als | Als het regent… |
| present / future | als | Als je klaar bent… |
| condition ("if") | als | Als het kan… |
| question ("when?") | wanneer | Wanneer kom je? |
| unknown / uncertain time | wanneer | …niet wanneer hij komt |
The cleanest minimal pair: Toen het regende, bleven we binnen (that one time it rained, we stayed in) vs. Als het regent, blijven we binnen (whenever it rains, we stay in). Same weather, but toen = once in the past, als = the general rule.
Common Mistakes
❌ Als ik gisteren thuiskwam, was er niemand.
Incorrect — a single past event needs toen, not als.
✅ Toen ik gisteren thuiskwam, was er niemand.
When I got home yesterday, there was no one there.
❌ Toen het regent, neem ik de bus.
Incorrect — habitual present takes als; toen is past-only.
✅ Als het regent, neem ik de bus.
When it rains, I take the bus.
❌ Ik weet niet als hij komt.
Incorrect for 'when' — an unknown time needs wanneer (als here would mean 'if').
✅ Ik weet niet wanneer hij komt.
I don't know when he's coming.
❌ Wanneer ik klein was, speelde ik veel buiten.
Incorrect — a single past stretch takes toen, not wanneer.
✅ Toen ik klein was, speelde ik veel buiten.
When I was little, I played outside a lot.
❌ Ik kom langs wanneer ik tijd heb.
Stilted — a plain future statement normally uses als, not wanneer.
✅ Ik kom langs als ik tijd heb.
I'll come by when I have time.
Key Takeaways
- Single past event → toen. This is the rule English speakers must over-learn: "when I was / when he came" is toen, never als.
- Repeated/habitual or non-past → als — and the same word means if ("Als het kan").
- In the past, the line is once (toen) vs. every time (als): Toen het regende (once) vs Als het regende / als het regent (whenever).
- Question or unknown time → wanneer; in plain statements, prefer als — wanneer there sounds formal.
- All three send the verb to the end of their clause.
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Start learning Dutch→Related Topics
- Toen vs Dan: Two Words for 'Then'B1 — English 'then' covers both past narration and present/future sequences; Dutch splits it. Toen is 'then / at that time' in past storytelling; dan is 'then / next' in present and future sequences and 'in that case'. This page gives the tense-based decision rule, head-to-head pairs, the inversion both trigger, and the errors English speakers make.
- Temporal Conjunctions: Toen, Als, Wanneer, Terwijl, NadatB1 — How Dutch carves up 'when' and 'while' — the crucial toen/als/wanneer split, plus terwijl, voordat, nadat, zodra, sinds and totdat.
- Als vs Dan in ComparisonsA2 — After a comparative, Dutch uses dan (groter dan ik, meer dan tien); for equality, it uses zo + adjective + als (net zo groot als). English speakers don't have this problem from their own language, but they hear native speakers say the substandard 'groter als' everywhere. This page gives the clean written rule, head-to-head pairs, and the reason 'groter als' is a shibboleth.
- Of vs Als: 'If' = Whether or Condition?B1 — English 'if' does two jobs that Dutch keeps strictly apart. Of is 'whether' — it introduces an indirect yes/no question ('Ik weet niet of hij komt'). Als is 'if' in the conditional sense — it introduces a real condition ('Als het regent, blijf ik thuis'). The test is simple: if you could swap 'if' for 'whether', use of; if it states a condition, use als. This page gives the rule, head-to-head pairs, and the errors English speakers make most.