Ich buche den Freizeitausgleich im Arbeitszeitkonto.

Here buchen means to enter, record, or post something in a system or account.

In workplace, HR, payroll, and accounting German, buchen is often used for making an official entry. So in this sentence it is not about reserving a flight or hotel. It is more like logging or posting the time off in the working-time system.

Because Freizeitausgleich is the direct object of buche, so it must be in the accusative case.

The noun is masculine:

• nominative: der Freizeitausgleich
• accusative: den Freizeitausgleich

So:

• Der Freizeitausgleich ist genehmigt. = subject, nominative
• Ich buche den Freizeitausgleich. = direct object, accusative

Freizeitausgleich means time off given as compensation, usually for overtime or extra hours worked.

It is not quite the same as:

• Urlaub = vacation/annual leave
• Pause = break
• Feierabend = time after work
• Überstundenvergütung = overtime pay

So Freizeitausgleich is specifically time off instead of money, or compensatory time.

An Arbeitszeitkonto is a system or balance where a company tracks working hours.

It can include things like:

• regular hours worked
• overtime
• minus hours
• time off taken to balance extra hours

In English, depending on the company or context, it might be translated as:

• working time account
• flexitime account
• time bank

It is not a financial bank account, even though Konto literally means account.

im is a contraction of in dem.

So:

• im = in dem

Since Arbeitszeitkonto is neuter:

• das Arbeitszeitkonto
• dative: dem Arbeitszeitkonto

That gives:

• in dem Arbeitszeitkonto
• contracted: im Arbeitszeitkonto

So the sentence literally has the article built into im.

This is about how in works in German.

in can take:

• dative for location or state
• accusative for direction or movement into something

So:

• im = in dem = dative
• ins = in das = accusative

In this sentence, the idea is that the entry is being recorded in the account/system, so German treats it as the place or context where the booking appears. That is why im Arbeitszeitkonto is natural here.

Very roughly:

• im = in the account
• ins = into the account

Because German very often builds compound nouns by joining words together.

Here:

• Arbeit = work
• Zeit = time
• Konto = account

Together: Arbeitszeitkonto = working-time account

A useful rule is that the last part of the compound is the main noun. It determines:

• the basic meaning
• the grammatical gender

So:

• das Konto is neuter
• therefore das Arbeitszeitkonto is also neuter

The same idea applies to Freizeitausgleich:

• the head word is Ausgleich
• der Ausgleich is masculine
• so der Freizeitausgleich is masculine

Yes. German word order is flexible, but in a normal main clause the conjugated verb usually stays in second position.

So all of these are possible:

• Ich buche den Freizeitausgleich im Arbeitszeitkonto.
• Den Freizeitausgleich buche ich im Arbeitszeitkonto.
• Im Arbeitszeitkonto buche ich den Freizeitausgleich.

The meaning is basically the same, but the first element gets more emphasis.

Yes. Depending on the situation, you might also hear:

• eintragen = enter
• erfassen = record/input
• verbuchen = post formally
• einbuchen = book/register into a system

For example:

• Ich trage den Freizeitausgleich im Arbeitszeitkonto ein.
• Ich erfasse den Freizeitausgleich im System.

But buchen sounds very natural in administrative, HR, or accounting-style language.

It sounds most natural in a workplace or HR context. It has a slightly administrative tone.

A native speaker would understand it easily, but it sounds like something you might say when talking about:

• a time-tracking system
• payroll
• overtime management
• internal company processes

In casual conversation, someone might use simpler wording, depending on the company and system they use.