Ich kann im Moment nicht kommen.

Because können is a modal verb. In German, modal verbs often work together with another verb:

• kann = the conjugated modal verb
• kommen = the main verb in the infinitive

In a normal main clause, the conjugated verb goes in second position, and the infinitive goes to the end:

• Ich kann ... kommen.

This is a very common German pattern:

• Ich will gehen.
• Sie muss arbeiten.
• Wir dürfen bleiben.

kann is the 1st person singular present tense form of können:

• ich kann
• du kannst
• er/sie/es kann
• wir können
• ihr könnt
• sie/Sie können

A learner often notices that the vowel changes from ö in können to a in kann. That is normal for this verb.

Because when a modal verb is used in a main clause, the other verb usually goes to the end of the clause in the infinitive.

So the structure is:

• subject: Ich
• finite verb in second position: kann
• other information: im Moment nicht
• infinitive at the end: kommen

This is one of the most important German word-order patterns to learn.

After a modal verb like können, German uses the bare infinitive, not zu + infinitive.

So you say:

• Ich kann kommen.

not:

• Ich kann zu kommen. ❌

Common modal verbs that work this way include:

• können
• müssen
• wollen
• dürfen
• sollen
• mögen

im Moment is a time expression meaning at the moment or for the moment.

Grammatically:

• im = contraction of in dem
• Moment is a masculine noun: der Moment

So literally, im Moment comes from in dem Moment.

In this sentence, it functions like a temporal adverbial expression telling you when the speaker cannot come.

Because im is a very common contraction of:

• in + dem = im

German often combines certain prepositions and articles this way:

• in dem → im
• an dem → am
• zu dem → zum
• zu der → zur

So im Moment is the standard form, not something unusual.

Here, nicht is negating the action kommen. In sentences with an infinitive at the end, nicht often appears right before the infinitive if that is what is being negated:

• Ich kann im Moment nicht kommen.

That placement shows that the speaker is unable to come.

A useful rule of thumb:

• nicht often comes before the part it is closely negating
• but in practice, German nicht placement has patterns that you gradually get used to

In this sentence, the placement is completely natural and standard.

It is not the most natural version here.

Ich kann im Moment nicht kommen is the normal word order if you mean that, at the moment, you are unable to come.

If you say Ich kann nicht im Moment kommen, it sounds awkward because nicht is interrupting the time phrase in a way that German usually avoids in this context.

So for a learner, the best version to remember is:

• Ich kann im Moment nicht kommen.

They are similar, but not always identical.

• im Moment = at the moment, often a bit broader or slightly more neutral
• jetzt = now
• gerade = right now, often with a strong sense of what is happening at this exact time

Examples:

• Ich kann im Moment nicht kommen. = I can’t come at the moment.
• Ich kann jetzt nicht kommen. = I can’t come now.
• Ich kann gerade nicht kommen. = I can’t come right now.

In many everyday situations, these can overlap, but the nuance can be slightly different.

Not always. Depending on context, kommen can mean:

• to come
• to come over
• to arrive
• to attend
• to show up

So in real life, Ich kann im Moment nicht kommen could mean:

• I can’t come over right now.
• I can’t come there at the moment.
• I can’t make it right now.

The exact nuance depends on the situation.

Yes. The verb kann is in the present tense.

German often uses the present tense in situations where English also uses the present:

• I can’t come at the moment
• I’m not able to come right now

Nothing special is happening tense-wise here; it is a normal present-tense sentence.

Yes. German word order is flexible as long as the conjugated verb stays in second position in a main clause.

So you can also say:

• Im Moment kann ich nicht kommen.

That version puts more emphasis on im Moment.

Both are correct:

• Ich kann im Moment nicht kommen.
• Im Moment kann ich nicht kommen.

The meaning is very similar; the difference is mainly focus and emphasis.