what is it?
German offers three structurally distinct ways to express a causal relationship — that one event or state is the reason for another. The subordinating conjunctions weil and da introduce a subordinate clause with verb-final word order. The coordinating conjunction denn links two main clauses without changing word order. The prepositions wegen and aufgrund govern a noun phrase in the genitive and express the same cause nominally — without any clause at all. Choosing between the three depends on register, what you want to emphasize, and whether the cause is expressed as a clause or as a noun phrase.
when to use it
weil — the default choice for expressing a reason in speech and writing. Use it when the cause is new information or when you want to place it in focus. The weil-clause can follow or precede the main clause.
da — preferred in formal and written registers when the cause is already known to both speaker and reader. The da-clause almost always comes first, before the main clause.
denn — a coordinating conjunction that introduces a second main clause giving the reason for the first. It is common in writing and formal speech. Because it is a coordinator, it cannot open the sentence pair, and the verb stays in second position in the denn-clause.
wegen + genitive — used when the cause can be expressed as a noun phrase rather than a full clause. Common in both spoken and written German. Typical in formal writing when combined with a nominalized verb (e.g. wegen des starken Regens).
aufgrund + genitive — functionally identical to wegen but more formal and more common in written, official, or academic contexts.
deshalb / daher / folglich — adverbial connectors that introduce a result clause (the effect, not the cause). They occupy the first position of a main clause and push the verb to second position. Use them when you want to state the cause first and then draw the consequence.
formation
The table below summarises the structural pattern for each connector. «Clause A» is the main statement; «Clause B» is the cause or consequence.
| connector | type | word order in the cause/result clause | example skeleton |
|---|---|---|---|
| weil / da | subordinating conjunction | verb moves to final position | … , weil/da [subject … verb-final] |
| denn | coordinating conjunction | verb stays in second position | Clause A, denn [subject verb …] |
| wegen + genitive | preposition | no clause — noun phrase only | Wegen [genitive noun phrase] … |
| aufgrund + genitive | preposition | no clause — noun phrase only | Aufgrund [genitive noun phrase] … |
| deshalb / daher / folglich | adverbial connector | verb in second position (connector in first) | Clause A. Deshalb/Daher/Folglich [verb subject …] |
When converting a verb-based cause into a nominal phrase for wegen or aufgrund, you must nominalize the verb. German nominalizations are neuter and take a capital letter: regnen → das Regnen; or use a related noun: der Regen → wegen des Regens. Adjective attributes take genitive endings: wegen des starken Regens.
Genitive endings for the article and adjective in a masculine/neuter noun phrase (the most common pattern with wegen/aufgrund):
| gender | definite article (genitive) | adjective ending (genitive) | example |
|---|---|---|---|
| masculine | des | -en | wegen des starken Sturms |
| neuter | des | -en | aufgrund des schlechten Wetters |
| feminine | der | -en | wegen der hohen Nachfrage |
| plural | der | -en | aufgrund der steigenden Preise |
examples in context
common pitfalls
Full clause after wegen. wegen is a preposition and must be followed by a noun phrase in the genitive, never by a conjugated clause. «*Wegen es regnete, fiel das Konzert aus.» is ungrammatical. Use either the subordinate clause form — Weil es stark regnete, fiel das Konzert aus. — or the nominal form: Wegen des starken Regens fiel das Konzert aus.
Fronting a denn-clause. denn is a coordinating conjunction (like und or aber) and cannot open the sentence pair. «*Denn er krank war, konnte er nicht kommen.» is wrong. denn must appear between the two main clauses: Er konnte nicht kommen, denn er war krank. If you need the cause in first position, use weil or da instead.
Forgetting to nominalize when switching to nominal style. When you replace a weil-clause with a wegen/aufgrund phrase, the verb must become a noun. «*wegen regnen» is not a valid noun phrase. Nominalize the verb (das Regnen) or use the corresponding noun (der Regen) and apply the genitive: wegen des Regens.
Three sentences, graded here. Nothing is saved and no account is needed.
Die Heizung war den ganzen Winter ausgefallen, ___ mussten wir jeden Abend mit Decken warm bleiben.
Fill in the blank with the correct word to complete the sentence.