Ich soll heute länger im Büro bleiben.

Soll is the ich form of sollen, a modal verb.

In this sentence, sollen usually means something like:

• to be supposed to
• to be expected to
• to have been told to

So Ich soll heute länger im Büro bleiben often suggests that the idea comes from someone else’s instruction or expectation, for example a boss, a schedule, or a rule.

It is not just a simple personal wish like I want to stay longer. It has the feeling of I’m supposed to stay longer.

This is a very common question, because both can sometimes be translated with must / have to / should, depending on context.

A useful basic difference is:

• ich muss = I have to / there is a necessity
• ich soll = I am supposed to / someone expects this of me

So:

• Ich muss heute länger im Büro bleiben.
  = I have to stay longer today.
  This sounds like a necessity.

• Ich soll heute länger im Büro bleiben.
  = I’m supposed to stay longer today.
  This sounds like an instruction, expectation, or order.

In real life, the difference can sometimes be subtle, but sollen often points to an external source behind the obligation.

Because this is a sentence with a modal verb.

German modal verbs include:

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

When a modal verb is used with another verb:

• the modal verb is conjugated
• the main verb stays in the infinitive
• the infinitive usually goes to the end

So:

• Ich soll ... bleiben

That is why you get:

• Ich soll heute länger im Büro bleiben.

This is one of the most important sentence patterns in German.

Länger is the comparative form of lang, meaning longer.

Here it is used adverbially, meaning it describes how long the staying lasts.

So:

• lange bleiben = stay a long time
• länger bleiben = stay longer

It does not take an adjective ending here, because it is not directly describing a noun. It is describing the action bleiben.

Compare:

• ein langer Tag = a long day
  adjective before a noun

but

• Ich bleibe lange. = I’m staying a long time
  adverb

and

• Ich bleibe länger. = I’m staying longer
  comparative adverb

Because German does not always need to state the second part of the comparison.

Länger by itself can mean:

• longer than usual
• longer than expected
• longer than someone else
• longer than before

The comparison is understood from context.

If you want to state it explicitly, you can add als:

• Ich soll heute länger als gestern im Büro bleiben.
  = I’m supposed to stay longer in the office today than yesterday.

But in your sentence, the comparison is left unstated, which is completely normal.

Im is a contraction of in dem.

So:

• im Büro = in dem Büro

Here, in is used with the dative because the sentence describes location, not movement.

The idea is:

• Where am I staying?
  im Büro = in the office

German often uses this distinction:

• in + dative for location
• in + accusative for movement into

Compare:

• Ich bleibe im Büro.
  I stay in the office.
  location

• Ich gehe in das Büro.
  I go into the office.
  movement

That is why im Büro is correct here.

German word order is flexible, but there are common patterns.

In Ich soll heute länger im Büro bleiben, heute comes early because it gives the time information.

A very common tendency in German is:

• time before
• manner / degree
• place

So here:

• heute = time
• länger = degree / duration-related idea
• im Büro = place

This order sounds very natural.

Other orders are sometimes possible, but they can sound more marked or put emphasis on a different element.

Some alternatives are possible, but they do not all sound equally natural.

The most neutral version is:

• Ich soll heute länger im Büro bleiben.

You may also hear:

• Ich soll heute im Büro länger bleiben.

This is possible, but it puts the location a bit earlier and may shift the emphasis slightly.

But:

• Ich soll länger heute im Büro bleiben.

This sounds less natural in normal speech, because heute usually comes earlier than länger.

So the original sentence is a very good, standard word order choice.

Often, yes.

In this sentence, bleiben matches English stay very well:

• im Büro bleiben = stay in the office

But bleiben is a broader word than English stay in some contexts. It can also mean:

• remain
• keep being
• continue to be

For example:

• Er bleibt ruhig. = He remains calm.
• Bitte bleiben Sie sitzen. = Please remain seated.

So in your sentence, bleiben means stay, but it is useful to know that the verb has a wider range.

Because the subject is ich.

The infinitive is sollen, but in the present tense it changes depending on the subject:

• ich soll
• du sollst
• er/sie/es soll
• wir sollen
• ihr sollt
• sie/Sie sollen

So the sentence begins with:

• Ich soll ...

The second verb, bleiben, stays in the infinitive because it is part of the modal verb construction.

Yes, depending on context.

That is one reason sollen can be tricky for English speakers.

In many situations, Ich soll heute länger im Büro bleiben is best understood as:

• I’m supposed to stay longer in the office today

But in some contexts, English might also use:

• I should stay longer in the office today

Still, should in English often sounds like advice, while sollen often sounds more like an expectation or instruction from outside.

So if you want the safest interpretation, think of sollen here as:

• to be supposed to
• to be told to
• to be expected to

That usually gets the nuance right.