Det står ju i hyreskontraktet.

That is a very common question. In Swedish, stå does literally mean stand, but it is also used idiomatically about written text.

So:

• Det står i boken. = It says in the book.
• Vad står det på skylten? = What does the sign say?

In Det står ju i hyreskontraktet, står means is written or says.

Here det is a formal or dummy subject. Swedish often uses det in sentences where English might say it even though there is no real concrete thing being referred to.

So Det står i hyreskontraktet literally looks like It stands in the rental contract, but the real meaning is It says so in the rental contract or That is stated in the rental contract.

You do not usually need to search for a specific noun that det refers to.

Ju is a modal particle, and it is tricky because it often does not have a single direct English translation.

In this sentence, ju adds the feeling of:

• as you know
• after all
• obviously
• you know

So Det står ju i hyreskontraktet has a tone like:

• It’s in the rental contract, after all.
• It does say that in the rental contract, you know.
• But it’s written in the rental contract.

It often suggests that the speaker thinks this should already be clear or known.

Yes. Det står i hyreskontraktet is perfectly grammatical.

Without ju, the sentence sounds more neutral and factual:

• It says in the rental contract.

With ju, it sounds more like the speaker is reminding someone of something obvious or already established:

• But it says so in the rental contract, after all.

So ju changes the tone more than the basic meaning.

Swedish usually uses i for something written in a text, contract, book, law, article, and so on.

Examples:

• Det står i boken.
• Det står i lagen.
• Det står i mejlet.

So i hyreskontraktet is the normal choice because the information is contained in the document.

Using på would usually sound less natural here.

It is a compound noun:

• hyra = rent
• kontrakt = contract

Together:

• hyreskontrakt = rental contract / lease

Then the definite ending is added:

• hyreskontraktet = the rental contract

So the structure is:

• ett hyreskontrakt = a rental contract
• hyreskontraktet = the rental contract

Because Swedish usually puts definiteness at the end of the noun instead of using a separate word like English the.

So:

• ett kontrakt = a contract
• kontraktet = the contract

And with the compound noun:

• ett hyreskontrakt = a rental contract
• hyreskontraktet = the rental contract

That final -et is doing the job of English the.

The dictionary form is ett hyreskontrakt.

That tells you two things:

• the noun is common in the ett gender
• the indefinite singular form is hyreskontrakt

Then you build the definite singular as hyreskontraktet.

The word order is the normal Swedish main-clause order:

• Det = subject
• står = verb
• ju = sentence particle
• i hyreskontraktet = adverbial phrase

So the pattern is basically:

subject + verb + particle/adverbial

If you move something to the front, Swedish still keeps the verb in second position:

• I hyreskontraktet står det ju.

That is less neutral and puts more emphasis on in the rental contract.

Yes, you could, but it is slightly different in style.

• Det står i hyreskontraktet is very natural and idiomatic for written information.
• Det är skrivet i hyreskontraktet means It is written in the rental contract, and sounds a bit more explicit or formal.

In everyday Swedish, det står ... is often the most natural way to express this idea.

You change står to stod:

• Det stod ju i hyreskontraktet.

That means:

• It said so in the rental contract.
• It was written in the rental contract, after all.

This is useful if you are talking about a past disagreement or something someone should have noticed earlier.

Depending on tone, good translations include:

• It says so in the rental contract.
• It’s in the rental contract, after all.
• It does say that in the rental contract, you know.
• It’s clearly stated in the rental contract.

The best choice depends mostly on how strongly you want to reflect the nuance of ju.