Mit rejsekort ligger i lommen, så jeg behøver ikke købe en billet.

Rejsekort is a travel card used for public transport in Denmark.

It is one word because Danish, like German, very often makes compound nouns:

• rejse = travel / journey
• kort = card

So rejsekort literally means travel-card. In Danish, compounds are normally written as a single word.

Because rejsekort is a neuter noun.

In Danish:

• en nouns usually take min
• et nouns usually take mit

You say:

• et rejsekort
• therefore mit rejsekort

A useful rule: in a compound noun, the last part decides the gender. Since kort is neuter, rejsekort is neuter too.

Danish often uses a position verb where English would just use is.

Ligger literally means lies / is lying. For objects that are resting somewhere, Danish often prefers ligger:

• Bogen ligger på bordet = The book is on the table
• Nøglerne ligger i tasken = The keys are in the bag

So Mit rejsekort ligger i lommen is more idiomatic than using er.

In Danish, the definite article is usually attached to the end of the noun.

So:

• en lomme = a pocket
• lommen = the pocket

That -en ending is doing the job of English the.

Because Danish often leaves out the possessive when the owner is obvious from context, especially with body parts, clothing, and things closely connected to a person.

So i lommen can naturally mean in my pocket here, because the speaker is talking about their own travel card.

If you say i min lomme, it sounds more explicit or emphatic, for example if you want to contrast it with another pocket or another person’s pocket.

Here så means so or therefore.

It connects the two ideas:

• My travel card is in my pocket
• so I don’t need to buy a ticket

So it introduces the result or consequence.

Because here så is functioning as a conjunction meaning so.

When så introduces a new main clause as a conjunction, the clause keeps normal word order:

• så jeg behøver ikke købe en billet

That means:

• jeg = subject
• behøver = finite verb

If så were being used more like an adverb at the front of the clause, you could get inversion:

• så behøver jeg ikke købe en billet

But the sentence you have uses the conjunction pattern, which is very common.

Because in a Danish main clause, ikke usually comes after the finite verb.

So the pattern is:

• jeg = subject
• behøver = finite verb
• ikke = not
• købe = infinitive

That gives:

• jeg behøver ikke købe en billet

This is a very important Danish word-order rule.

After behøver, Danish often uses the infinitive directly, especially in negative sentences:

• jeg behøver ikke købe

This is very natural Danish.

You may also hear:

• jeg behøver ikke at købe

So in this kind of sentence, with or without at can occur, but leaving at out is very common.

Because the meaning is a ticket, not the ticket.

The speaker is not talking about one specific, already identified ticket. They mean any ticket they would otherwise have to buy.

So:

• en billet = a ticket
• billetten = the ticket

It is in the present tense:

• ligger = lies / is
• behøver = need

The sentence describes a present situation and its present consequence:

• the travel card is in the pocket now
• so there is no need to buy a ticket now

It is very natural here, especially in a negative sentence:

• jeg behøver ikke ... = I don’t need to ...

That pattern is extremely common in Danish.

In other contexts, Danish may express need in different ways, for example:

• jeg har brug for ... = I have need of / I need ...
• jeg skal ... = I have to / I need to, depending on context

But in this sentence, behøver ikke is exactly the natural choice.