Po pracy wolę odpoczywać u siebie niż w biurze.

Po can mean after in time expressions, and in this use it normally takes the locative case.

So:

• praca = work
• po pracy = after work

The form pracy is the locative singular of praca here.
(It happens to look the same as some other case forms, but in this sentence it is locative because po requires it.)

In Polish, subject pronouns are often omitted because the verb ending already shows who is doing the action.

Here, wolę means I prefer, so ja is unnecessary.

• (Ja) wolę = I prefer

You could say Ja wolę... if you want extra emphasis, for example to contrast with someone else, but in a neutral sentence it is usually left out.

Wolę is the 1st person singular form of the verb woleć, meaning to prefer.

A few common forms are:

• ja wolę = I prefer
• ty wolisz = you prefer
• on/ona/ono woli = he/she/it prefers
• my wolimy = we prefer
• wy wolicie = you (plural) prefer
• oni/one wolą = they prefer

So wolę odpoczywać literally means I prefer to rest / I prefer resting.

After woleć, Polish often uses an infinitive to say what someone prefers doing.

So the pattern is:

• wolę + infinitive

Examples:

• Wolę czytać. = I prefer to read.
• Wolę zostać w domu. = I prefer to stay at home.
• Wolę odpoczywać... = I prefer to relax/rest...

This is very natural and works much like English prefer to do or prefer doing.

This is about aspect, which is very important in Polish.

• odpoczywać = imperfective
• odpocząć = perfective

In this sentence, the speaker is talking about a general preference or habit after work, so the imperfective odpoczywać is the natural choice.

• Po pracy wolę odpoczywać... = After work, I prefer relaxing...

If you said wolę odpocząć, it would sound more like I’d prefer to get some rest / to rest once and complete that action, often in a more specific situation.

So:

• wolę odpoczywać = general, habitual preference
• wolę odpocząć = preference for one complete instance of resting

U siebie is an idiomatic expression meaning something like:

• at my own place
• at home
• in my own space

Literally, it is closer to at oneself’s place than just in the house.

Because the subject here is I (from wolę), u siebie means at my place / at home.

A useful point: u siebie changes its real-world meaning depending on the subject.

• Jestem u siebie. = I’m at my place.
• Jesteś u siebie. = You’re at your place.
• Czuje się u siebie. = He/She feels at home / in their own place.

Both can often be translated as at home, but they are not always exactly the same.

• w domu = in the house / at home
• u siebie = at one’s own place, in one’s own environment

U siebie emphasizes that it is your own place, not just any home or house. It can sound a bit more personal and contrast nicely with w biurze.

So in this sentence:

• u siebie highlights my own space
• w biurze highlights the office

That contrast is very natural: in my own place rather than in the office.

Here, siebie is the reflexive pronoun, and after u it is in the genitive:

• u + genitive
• therefore: u siebie

It is not swój because swój is a possessive adjective, and adjectives modify nouns:

• swój dom = one’s own house
• w swoim domu = in one’s own house

But in u siebie, there is no noun after it. It is a fixed expression using the reflexive pronoun, not a possessive adjective.

So:

• u siebie = at one’s own place
• w swoim domu = in one’s own house/home

Both are possible in Polish, but they are built differently.

Niż means than and is used in comparisons.

Here the comparison is:

• wolę odpoczywać u siebie niż w biurze
• literally: I prefer relaxing at my place rather than in the office

Polish often leaves out repeated words when they are understood. So the full idea is really:

• Wolę odpoczywać u siebie niż odpoczywać w biurze.

The second odpoczywać is omitted because it would be repetitive.

So niż introduces the second part of the comparison: than in the office.

Because w meaning in for a location takes the locative case.

• biuro = office
• w biurze = in the office

This is a static location, not movement.

Compare:

• Jestem w biurze. = I am in the office.
• Pracuję w biurze. = I work in the office.

So in your sentence, w biurze means the place where the relaxing would happen, and since it is a location, the locative is used.

Yes, Polish word order is fairly flexible, but different orders can sound more or less natural or change the emphasis.

The given sentence is very natural and neutral:

• Po pracy wolę odpoczywać u siebie niż w biurze.

You could also say:

• Wolę po pracy odpoczywać u siebie niż w biurze.

This is still understandable and natural, but the original version flows a bit more smoothly as a neutral statement.

In general:

• putting Po pracy first frames the time right away
• putting u siebie before niż w biurze helps the comparison sound clear

So yes, word order can move, but the original sentence is a very good default version.

It can cover both, depending on context.

Odpoczywać usually means:

• to rest
• to relax
• to take it easy / recover energy

So in this sentence, it is broader than just sleeping or doing nothing. It simply means spending time after work in a restful way.

That is why the sentence sounds natural with either interpretation in English, depending on context.