what is it?
A conditional relation links a condition to a consequence: if X holds, then Y follows. German offers several structurally distinct ways to express this. The most common is a subordinate clause introduced by wenn or falls. More formal registers use an unintroduced verb-first clause (the conjunction is dropped and the finite verb moves to position 1). Nominal style replaces the entire clause with bei + dative noun phrase or im Falle + genitive. Finally, es sei denn and sonst mark the exception or negative consequence. All four patterns are in active use; the choice is primarily one of register and style.
when to use it
wenn — the default choice in spoken and written German. Use it for real, open conditions in the present or future. It also covers repeated past events ("whenever"), so context disambiguates.
falls — signals that the condition is uncertain or that the speaker considers it less likely. Interchangeable with wenn in most contexts, but preferred when you want to mark contingency explicitly.
verb-first conditional (Sollten …, Haben Sie …) — formal written and spoken register: official letters, announcements, legal texts. The conjunction is omitted; the finite verb opens the clause. The main clause follows with normal or inverted word order.
bei + dative noun / im Falle + genitive — nominal style, common in formal prose, instructions, and signs. The condition is compressed into a noun phrase, avoiding a full clause.
es sei denn(, dass …) — introduces the one exception that would prevent the main clause from applying. Equivalent to English "unless".
sonst / andernfalls — states the negative consequence if the condition is not met. Equivalent to "otherwise". Sonst is colloquial; andernfalls is formal.
formation
The table below summarises the structural pattern for each conditional type. In every case the main clause follows the conditional element; if the conditional element stands first, the main clause begins with the finite verb (verb-second rule).
| type | structure | example (condensed) |
|---|---|---|
| wenn / falls | wenn/falls + subject + … + finite verb | Wenn es regnet, bleiben wir drinnen. |
| verb-first | finite verb + subject + … , main clause | Sollten Sie Fragen haben, melden Sie sich. |
| bei + dative | bei + dative noun phrase , main clause | Bei schlechtem Wetter findet das Fest drinnen statt. |
| im Falle + genitive | im Falle + genitive noun phrase , main clause | Im Falle eines Brandes verlassen Sie das Gebäude. |
| es sei denn | main clause , es sei denn(, dass + … + verb) | Wir gehen, es sei denn, es regnet. |
| sonst / andernfalls | imperative or statement , sonst/andernfalls + main clause | Beeil dich, sonst verpassen wir den Zug. |
Verb-first conditionals and Konjunktiv II. The verb-first pattern most often uses sollten (Konjunktiv II of sollen) to signal polite uncertainty, or the present indicative for more direct conditions (e.g. Haben Sie Fragen, …). Both are standard.
bei + dative: adjective endings. When an adjective precedes the noun inside a bei phrase with no article, it takes strong (unpreceded) dative endings: bei schlechtem Wetter (neuter dative strong), bei starkem Regen (masculine dative strong).
examples in context
common pitfalls
Stacking wenn onto a verb-first clause. The verb-first pattern already encodes the conditional meaning; adding wenn is redundant and ungrammatical. ✗ Wenn sollten Sie Fragen haben, … — choose one or the other: Wenn Sie Fragen haben, … or Sollten Sie Fragen haben, ….
Putting a full clause after bei. bei is a preposition and requires a noun phrase in the dative — never a clause with a subject and finite verb. ✗ bei das Wetter ist schlecht is doubly wrong: das is not dative, and a finite verb cannot follow. Write bei schlechtem Wetter or use a wenn-clause instead.
Misreading es sei denn as «that is». Learners sometimes confuse es sei denn with the phrase das heißt («that is / i.e.»). Es sei denn means «unless» — it introduces the one condition that would make the main clause false. In the sentence Wir gehen, es sei denn, es regnet, rain is the single exception that cancels the plan, not a clarification of it.
Three sentences, graded here. Nothing is saved and no account is needed.
Wenn ein Waldbrand ___, müssen die Feuerwehrleute sofort eingreifen. (ausbrechen)
Fill in the blank with the correct form of the verb in parentheses to complete the conditional clause.