Als vs Wanneer: Two Ways to Say 'When' in Dutch

Choose als for conditions and wanneer for explicit time questions, while recognizing their overlap.

NL006 ยท NL ยท A2 / B1 ยท grammar

The question

Why do Dutch speakers say Als ik tijd heb and Wanneer kom je?

Als commonly introduces a condition ('if') or a time situation ('when'): Als het regent, blijf ik thuis (If/when it rains, I stay home). Wanneer specifically asks about time and can introduce temporal subordinate clauses: Wanneer begint de film? (When does the film start?). In time clauses, als and wanneer often overlap, so they are not strict opposites.

Compare typical uses

FunctionDutchEnglish
ConditionAls je wilt, kunnen we gaan.If you want, we can leave.
Time questionWanneer begint de les?When does the lesson begin?
Time clauseWanneer ik thuiskom, bel ik je.When I get home, I'll call you.
Repeated situationAls ik vrij ben, ga ik wandelen.When I have time off, I go walking.

Both als and wanneer can introduce subordinate clauses with verbs at the end: als ik thuis ben; wanneer de trein vertrekt. When the subordinate clause opens the sentence, the main clause has inversion: Als ik klaar ben, bel ik je. For a one-time event in the past, toen is often preferred: Toen ik klein was, woonde ik in Gent.

Common mistake

Avoid using wanneer as the normal equivalent of 'if' in a hypothetical condition; Als je tijd hebt, kom dan langs is the straightforward choice. Do not use als in direct time questions such as *Als begint de film?

Remember

Use als for conditions and many time clauses, wanneer for time questions and temporal clauses, and toen for many specific past-time situations.

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