Ob vs. Wenn in German: Clear Rules, Examples & Key Differences

Introduction

In German, the words “ob” and “wenn” are both conjunctions that introduce subordinate clauses, but they are used in different contexts. Understanding the difference between these two words is essential for constructing accurate and meaningful sentences. This article will explain the usage of “ob” and “wenn,” provide example sentences, and discuss their sentence structures.

Understanding the Usage of “ob” and “wenn”

Both “ob” and “wenn” introduce subordinate clauses, but they serve different purposes and are not interchangeable.

When to Use “ob”

“Ob” is used to introduce indirect yes-or-no questions and expresses uncertainty or doubt. It translates to “if” or “whether” in English when discussing possibilities.

You can get more details about German indirect questions: here.

When to Use “wenn”

“Wenn” is used to introduce conditional clauses or to indicate a point in time. It translates to “if” or “when” in English, depending on the context.

Detailed Usage of “ob” and “wenn”

Using “ob” in German Sentences

“Ob” introduces indirect questions, especially when the answer is uncertain. It is often used after verbs like “wissen” (to know), “fragen” (to ask), “sich wundern” (to wonder), etc.

Examples:

• • Ich weiß nicht, ob er kommt. – I don’t know if he is coming.

• • Sie fragt, ob du Zeit hast. – She asks if you have time.

Using “wenn” in German Sentences

“Wenn” is used in two main contexts:

• • Conditional Sentences: To express conditions or hypothetical situations.

• • Temporal Sentences: To refer to repeated events in the past, present, or future.

Examples:

• • Wenn es regnet, bleiben wir zu Hause. – If it rains, we’ll stay home.

• • Wenn ich Zeit habe, besuche ich dich. – When I have time, I’ll visit you.

Example Sentences Comparing “ob” and “wenn”

Below is a table with example sentences using “ob” and “wenn,” along with their English translations:

German Sentence	English Translation
Ich weiß nicht, ob sie heute kommt.	I don’t know if she is coming today.
Er fragt mich, ob ich mitkommen möchte.	He asks me if I would like to come along.
Kannst du mir sagen, ob der Zug pünktlich ist?	Can you tell me if the train is on time?
Ruf mich an, wenn du angekommen bist.	Call me when you have arrived.
Wenn du Hilfe brauchst, sag Bescheid.	If you need help, let me know.
Wenn es kalt ist, ziehe ich einen Mantel an.	When it is cold, I put on a coat.
Sie möchte wissen, ob du kommen kannst.	She wants to know if you can come.
Wir gehen spazieren, wenn das Wetter schön ist.	We go for a walk when the weather is nice.
Er überlegt, ob er das Angebot annimmt.	He is considering whether to accept the offer.
Wenn ich reich wäre, würde ich um die Welt reisen.	If I were rich, I would travel the world.

Sentence Structure with “ob” and “wenn”

Both “ob” and “wenn” introduce subordinate clauses, which affect the word order in German sentences.

Word Order in Subordinate Clauses

In German subordinate clauses, the conjugated verb moves to the end of the clause.

Example with “ob”:

• • Ich frage mich, ob er kommen wird.

Example with “wenn”:

• • Wenn es regnet, bleiben wir zu Hause.

Position of Subordinate Clauses

Subordinate clauses can appear at the beginning or at the end of a sentence.

“Wenn” Clause at the Beginning:

• • Wenn ich Zeit habe, besuche ich dich. – When I have time, I’ll visit you.

“Wenn” Clause at the End:

• • Ich besuche dich, wenn ich Zeit habe. – I’ll visit you when I have time.

“Ob” Clause at the Beginning (Less Common):

• • Ob er kommt, weiß ich nicht. – Whether he is coming, I don’t know.

Note on “Ob” Clauses

While it’s possible to start a sentence with an “ob” clause, it’s less common and often used for emphasis or stylistic reasons.

For more on sentence structure, see our article on German Word Order.

Common Mistakes When Using “Ob” and “Wenn” in German

Learning the difference between “ob” and “wenn” can be tricky for German learners. Many mistakes happen because both words can translate to “if” in English. Below are some common errors and how to fix them.

1. Using “ob” Instead of “wenn” in Conditional Sentences

❌ Incorrect: Ich gehe ins Kino, ob es regnet.
✅ Correct: Ich gehe ins Kino, wenn es regnet.
Explanation:

• “Wenn” is used in conditional sentences (if something happens, then something else happens).
• “Ob” is only for indirect yes-no questions, not conditions.

2. Using “wenn” Instead of “ob” in Indirect Questions

❌ Incorrect: Ich weiß nicht, wenn er kommt.
✅ Correct: Ich weiß nicht, ob er kommt.
Explanation:

• “Ob” is necessary for indirect questions.
• “Wenn” is incorrect because it expresses conditions or repeated events, not uncertainty.

3. Using “ob” Instead of “wenn” for Time Expressions

❌ Incorrect: Ob ich Zeit habe, rufe ich dich an.
✅ Correct: Wenn ich Zeit habe, rufe ich dich an.
Explanation:

• “Wenn” is used for time-related actions (when something happens).
• “Ob” would be wrong because it does not indicate time.

4. Confusing “ob” and “falls”

❌ Incorrect: Ob es regnet, nehme ich einen Schirm mit.
✅ Correct: Falls es regnet, nehme ich einen Schirm mit.
Explanation:

• “Falls” is more formal and is used like “in case” or “if” in English.
• “Ob” is incorrect because this is a conditional sentence, not an indirect question.

5. Incorrect Word Order in Subordinate Clauses

❌ Incorrect: Ich frage mich, ob kommt er.
✅ Correct: Ich frage mich, ob er kommt.
❌ Incorrect: Wenn habe ich Zeit, rufe ich dich an.
✅ Correct: Wenn ich Zeit habe, rufe ich dich an.
Explanation:

• In subordinate clauses, the conjugated verb moves to the end of the clause.

Quick Recap

✔ Use “ob” for indirect yes-no questions (Ich frage mich, ob…).
✔ Use “wenn” for conditions and time (Wenn es regnet, bleibe ich zu Hause.).
✔ Use “falls” instead of “wenn” when you mean “in case” or “if” (Falls du Hilfe brauchst, ruf mich an.).
✔ Keep the verb at the end in subordinate clauses (Ich weiß nicht, ob er kommt.).

Practice Exercises: Ob vs. Wenn

Test your understanding of “ob” and “wenn” with these exercises. Choose the correct word for each sentence and check the answers directly after each section.

1. Fill in the Blanks

Complete the sentences with “ob” or “wenn”.

1. Ich weiß nicht, ___ er morgen Zeit hat.
2. Ruf mich an, ___ du zu Hause bist.
3. Sie fragt mich, ___ ich mit ihr ins Kino gehe.
4. Ich komme später, ___ ich mit der Arbeit fertig bin.
5. Weißt du, ___ der Bus pünktlich ist?
6. ___ es regnet, nehme ich einen Regenschirm mit.
7. Ich frage mich, ___ das Restaurant geöffnet hat.
8. ___ du Hunger hast, kannst du dir etwas zu essen holen.
9. Er überlegt, ___ er das Jobangebot annimmt.
10. Ich gehe schwimmen, ___ das Wetter schön ist.

Answers:

1. ob
2. wenn
3. ob
4. wenn
5. ob
6. wenn
7. ob
8. wenn
9. ob
10. wenn

2. Rewrite the Sentences

Rephrase the sentences by replacing direct questions with indirect ones using “ob”.

Example:

• Direct: Kommt sie heute?
• Indirect: Ich weiß nicht, ob sie heute kommt.

1. Hat er den Termin bestätigt?
2. Bleibt das Café heute offen?
3. Kommt der Bus pünktlich an?
4. Kannst du mir helfen?
5. Ist das Hotel teuer?

Answers:

1. Ich weiß nicht, ob er den Termin bestätigt hat.
2. Ich frage mich, ob das Café heute offen bleibt.
3. Kannst du mir sagen, ob der Bus pünktlich ankommt?
4. Ich möchte wissen, ob du mir helfen kannst.
5. Sie fragt sich, ob das Hotel teuer ist.

3. Choose the Correct Sentence

Identify the correct sentence in each pair.

1. Ich frage mich, wenn sie kommt.
   Ich frage mich, ob sie kommt.

2.  Ob ich Zeit habe, helfe ich dir.
    Wenn ich Zeit habe, helfe ich dir.

3. Er weiß nicht, ob der Bus fährt.
   Er weiß nicht, wenn der Bus fährt.

4.  Wenn er den Job bekommt, fragt er sich.
    Er fragt sich, ob er den Job bekommt.

5.  Ich überlege, ob ich mitkomme.
   Ich überlege, wenn ich mitkomme.

Answers:

1. Ich frage mich, ob sie kommt.
2. Wenn ich Zeit habe, helfe ich dir.
3. Er weiß nicht, ob der Bus fährt.
4. Er fragt sich, ob er den Job bekommt.
5. Ich überlege, ob ich mitkomme.

4. Translation Practice

Translate the following sentences into German using “ob” or “wenn”.

1. I don’t know if she is coming.
2. Call me when you arrive.
3. He is asking if the restaurant is open.
4. If you are tired, go to bed.
5. She wonders if he has a dog.

Answers:

1. Ich weiß nicht, ob sie kommt.
2. Ruf mich an, wenn du angekommen bist.
3. Er fragt, ob das Restaurant geöffnet ist.
4. Wenn du müde bist, geh ins Bett.
5. Sie wundert sich, ob er einen Hund hat.

Conclusion

Understanding the difference between “ob” and “wenn” is crucial for proper German grammar. Use “ob” for indirect yes-or-no questions and expressions of uncertainty. Use “wenn” for conditional statements and to refer to time when events happen. Paying attention to their usage and sentence placement will help you communicate more accurately in German.

Frequently Asked Questions

Can “ob” and “wenn” be used interchangeably?

No, “ob” and “wenn” serve different purposes. “Ob” is used for indirect questions and uncertainty, while “wenn” is used for conditions and time references.

How do I know when to use “wenn” as “if” or “when”?

Context determines the translation. If it introduces a condition, translate it as “if.” If it refers to a time when something happens, translate it as “when.”

Can I start a sentence with an “ob” clause?

Yes, but it’s less common. Starting a sentence with an “ob” clause is possible but often used for emphasis.

Does the verb always go to the end in clauses with “ob” and “wenn”?

Yes, in subordinate clauses introduced by “ob” and “wenn,” the conjugated verb moves to the end of the clause.

Are there other words similar to “ob” and “wenn” that I should know?

Yes, words like “als” (when, for past events) and “falls” (in case) are also used in German and have specific uses. Learning them can further improve your language skills. You can read more about “als” vs “wann” and “wenn”: here.