“Müssen” Conjugation: Learn How to Conjugate the German Verb “Müssen” in All Tenses

Müssen is a common German modal verb that means “to have to” or “must.” Whether you come across the verb on instructional signs or hear it in conversation, to fully understand all the things you might “have to do,” it’s important to know your müssen conjugation.

If you want to learn how to correctly conjugate müssen, you’ve come to the right place. This guide covers all the different forms of the verb.

What does “Müssen” mean?

In German, we use müssen to talk about obligation. If someone must or has to do something, you can get that meaning across with this useful modal verb.

For example:

• Ich muss arbeiten. – I have to work.
• Wir müssen in die Schule gehen. – We have to go to school.

In general, whenever you need to talk about something that has to happen, you can use the verb müssen. However, there is one thing that English speakers need to look out for.

In English, the negative form of must (i.e., must not) means “to not be allowed to” – not “to not have to.”

For example:

• You must not touch the stove. (Because it’s hot.)
• You mustn’t be late to work. (Because you’ll get into trouble.)

In German, however, nicht müssen means “to not have to” – it has nothing to do with what you are or are not allowed. For example:

• Wir müssen nicht in die Schule gehen. – We don’t have to go to school. (Because it’s Saturday.)

So, nicht müssen and “must not” do not actually correspond. If you want to talk about something that is prohibited in German (i.e., something that must not happen), you can use the verb dürfen (= to be allowed to, may) instead. Müssen always means either “to have to” or “to not have to.”

Here is a little table to help you remember this:

müssen	to have to, must
nicht müssen	to not have to
dürfen	to be allowed to, may
nicht dürfen	to not be allowed to

How to Use “Müssen”

Before you start learning the specifics of müssen conjugation, it’s important to know how Germans use this verb. I’ve mentioned already that müssen is a modal verb. But what does that mean?

Simply put, modal verbs are verbs that are used together with other verbs. Müssen doesn’t carry a lot of meaning on its own – it’s there to indicate that someone has an obligation to do something.

Take a look at the following sentence, for example:

• Ich lese ein Buch. – I am reading a book.

From this sentence, all you know is that someone is reading a book – that’s all. But if you add müssen to the mix, the sentence changes its meaning somewhat and gives you more information about what might be happening.

• Ich muss ein Buch lesen. – I have to read a book. (Because my teacher told me to.)

In this case, lesen (= to read) is a lexical verb – it carries the meaning. Müssen is a modal verb – it’s there to indicate modality. Lexical verbs can be used on their own, but modal verbs are always accompanied by another verb.

Now, let’s get into the details of müssen conjugation.

“Müssen” Conjugation in Present Tense (Präsens)

The reason why some may find the müssen conjugation a little bit tricky is that, much like all the other modal verbs, müssen is an irregular verb. This means that it doesn’t follow the usual conjugation patterns that you may be used to. Unfortunately, to be able to conjugate müssen correctly, you will have to memorize the following forms.

Let’s start with the present tense.

Singular

ich muss	I must / have to
du musst	you must / have to
er/sie/es muss	he/she/it must / has to

There are two things to note here: First, notice how in singular present tense, the vowel “ü” changes to “u.” Second, the first and third person both don’t have their usual, regular endings. Saying “ich musse” or “ich müsse” would be wrong – the correct way to do müssen conjugation is to say “ich muss.” The same goes for “er muss” – never say “er musst” or “er müsst.”

Plural

wir müssen	we must / have to
ihr müsst	you must / have to
sie/Sie müssen	they/you must / have to

Luckily, the plural present tense forms of müssen are all regular. There’s nothing to stress over here!

Examples:

• Ihr müsst im Voraus zahlen. (You have to pay in advance.)
• Wir müssen hier warten. (We have to wait here.)
• Ich muss zum Arzt gehen. (I have to go to the doctor).

“Müssen” Conjugation in Simple Past Tense (Präteritum)

If you’ve learned about the simple past tense form (or Präteritum) before, you may know that, in general, Germans use this tense in written rather than spoken form in German. In spoken German, it’s often preferred to use the present perfect tense (or Perfekt) when talking about the past.

However, this is a little bit different when it comes to the müssen conjugation.

It is much more common to use Präteritum instead of Perfekt with modal verbs such as müssen. We will still cover both forms, but keep in mind that the simple past tense is what you will usually come across with müssen.

Singular

ich musste	I had to
du musstest	you had to
er/sie/es musste	he/she/it had to

Plural

wir mussten	we had to
ihr musstet	you had to
sie/Sie mussten	they/you had to

Again, pay attention to how the vowel “ü” changes to “u” in Präteritum.

Examples:

• Ich musste draußen gehen. (I had to go outside.)
• Sie mussten nicht kommen. (You did not have to come.)

“Müssen” Conjugation in Present Perfect Tense (Perfekt)

The müssen conjugation gets a little bit tricky in the present perfect tense. I’ll explain why – but first, let’s take a look at the forms:

Singular

ich habe gemusst/müssen	I had to / have had to
du hast gemusst/müssen	you had to / have had to
er/sie/es hat gemusst/müssen	he/she/it had to / have had to

Plural

wir haben gemusst/müssen	we had to / have had to
ihr habt gemusst/müssen	you had to / have had to
sie/Sie haben gemusst/müssen	they/you had to / have had to

As you may have noticed, there are a couple of options when it comes to the müssen conjugation in Perfekt.

In general, the present perfect consists of two parts – a helping (auxiliary) verb and the past participle of the verb you’re conjugating.

For example:

• ich habe gesagt (I said / have said)

Naturally, you may therefore think that the correct form of müssen in the present perfect tense would be “ich habe gemusst.” However, this is only the case if you’re using müssen as a lexical verb. In practice, this almost never happens. In most cases, you will only see müssen used as a modal verb, in which case, the correct conjugation will look different.

When using müssen as a modal verb, you do not need to use the past participle of the verb (i.e., gemusst). Instead, use the infinitive form of müssen (i.e., müssen).

This infinitive form, which is used in all perfect tenses (including the past perfect and the future perfect), is called “Ersatzinfinitiv” (substitute infinitive), and it sounds much more natural to native German speakers.

Here are some example sentences to show you how to use müssen correctly in this tense:

• Wir haben das Buch lesen müssen. (We had to read the book.)
• Du hast warten müssen. (You had to wait.)

Note: Notice the word order of the above example sentences. The verb müssen always goes to the very end of the sentence – it comes after the lexical verb.

“Müssen” Conjugation in Past Perfect Tense (Plusquamperfekt)

Much like in the present perfect tense, you will mostly come across the past perfect tense with the “Ersatzinfinitiv” – i.e., instead of using “gemusst,” German speakers will use “müssen.” This is always the case if you’re using müssen as a modal verb.

Here is what the müssen conjugation looks like in Plusquamperfekt:

Singular

ich hatte gemusst/müssen	I had had to
du hattest gemusst/müssen	you had had to
er/sie/es hatte gemusst/müssen	he/she/it had had to

Plural

wir hatten gemusst/müssen	we had had to
ihr hattet gemusst/müssen	you had had to
sie/Sie hatten gemusst/müssen	they/you had had to

Examples:

• Er hatte in die Kirche gehen müssen. (He had had to go to church.)
• Sie hatten nicht mitkommen müssen. (They hadn’t had to come along.)

“Müssen” Conjugation in Future Tense (Futur I)

When it comes to the müssen conjugation in the future tense, it’s all relatively simple. All you need to know is how to conjugate the German auxiliary verb werden. Other than that, you just need the infinitive form of müssen, and you’re good to go!

Singular

ich werde müssen	I will have to
du wirst müssen	you will have to
er/sie/es wird müssen	he/she/it will have to

Plural

wir werden müssen	we will have to
ihr werdet müssen	you will have to
sie/Sie werden müssen	they/you will have to

Examples:

• Sie wird zum Zahnarzt gehen müssen. (She will have to go to the dentist.)
• Du wirst ihn zurückrufen müssen. (You will have to call him back.)

Note: Notice how müssen goes right to the end of the sentence. This is always the case with sentence structures like these – the modal verb comes after the lexical verb.

“Müssen” Conjugation in Future Perfect Tense (Futur II)

Last, but not least, we have the future perfect tense. This tense isn’t used very often in German, but to fully master the müssen conjugation, you should be aware of it.

Don’t worry if you find this a little bit overwhelming! Even native German speakers sometimes struggle with complex structures like these.

Singular

ich werde gemusst haben/haben müssen	I will have had to
du wirst gemusst haben/haben müssen	you will have had to
er/sie/es wird gemusst haben/haben müssen	he/she/it will have had to

Plural

wir werden gemusst haben/haben müssen	we will have had to
ihr werdet gemusst haben/haben müssen	you will have had to
sie/Sie werden gemusst haben/haben müssen	they/you will have had to

Much like with the other perfect forms, you have two options in Futur II:

• If you’re using müssen as a lexical verb, use the past participle form (e.g., “ich werde gemusst haben”). You are unlikely to use or see this.
• If you’re using müssen as a modal verb, use the “Ersatzinfinitiv.” For example: “ich werde (gehen) haben müssen.” As müssen is mainly used as a modal verb, this is the form you will come across in most cases.

Example:

• Sie wird in die Schule gehen haben müssen. (She will have had to go to school.)

Other Forms of “Müssen”

That’s almost it for the müssen conjugation! There are only a couple more forms that you should be aware of. These are:

Present Participle (Partizip I)

The present participle of müssen is “müssend” (= having to).

Important: The German present participle is different from the English one. Germans mainly use the present participle as an adjective – never as a verb. “I am speaking” in German is “Ich spreche,” never “Ich bin sprechend.”

Past Participle (Partizip II)

We’ve already somewhat covered this in the müssen conjugation in perfect tenses, but it won’t hurt to remind ourselves. The past participle of müssen is “gemusst.”

Subjunctive (Konjunktiv II)

The subjunctive is a grammatical mood that is used to express things that aren’t necessarily real. It can also be used when you’re trying to be more polite when asking questions.

If you’d like to learn more about the subjunctive forms of müssen, check out this amazing guide to modal verbs in the subjunctive by DeutschLera:

Learn More

If you’ve read through this whole guide and still feel up to learning more about German grammar, why not check out some of our other useful guides? Here are some options:

• “Können” Conjugation: Learn to Conjugate the German Verb “Können”
• German Tenses: When and How to Use Them
• A Complete Guide to Understanding German Pronouns