Du kan aktivera simkortet förutsatt att kundnumret är rätt.

Because -et is the definite article suffix for many neuter nouns in Swedish.

• ett simkort = a SIM card
• simkortet = the SIM card

Unlike English, Swedish usually adds the definite article to the end of the noun instead of putting a separate word like the in front.

This is because kundnummer is a neuter noun ending in -er, and in the definite singular it becomes kundnumret.

• ett kundnummer = a customer number
• kundnumret = the customer number

Many Swedish neuter nouns ending in -el, -en, or -er drop the extra vowel before adding -et. So:

• nummer → numret
• kundnummer → kundnumret

This is a normal pattern, not something unique to this word.

Because after a modal verb like kan (can), Swedish uses the infinitive without att.

So:

• Du kan aktivera = You can activate
• not Du kan att aktivera

This is similar to English, where we say can activate, not can to activate.

Other common modal verbs that work the same way:

• ska = will / shall / going to
• vill = want to
• måste = must / have to
• bör = should
• får = may / am allowed to

Examples:

• Jag vill köpa det.
• Hon måste gå nu.

Förutsatt att means provided that, as long as, or on the condition that.

It introduces a condition:

• Du kan aktivera simkortet förutsatt att kundnumret är rätt.

So the activation is possible only if the condition is met.

It is a fairly formal or neutral expression. In everyday Swedish, you might also see:

• om = if
• så länge = as long as

But förutsatt att is very useful in formal instructions, contracts, customer service language, and written information.

Because in Swedish subordinate clauses, the normal word order is:

subject + sentence adverb + verb

In this clause:

• kundnumret = subject
• är = verb
• rätt = complement

So kundnumret är rätt is the normal order.

The inversion you may know from main clauses does not happen here.

Compare:

• Main clause: Nu är kundnumret rätt.
• Subordinate clause: ... att kundnumret är rätt.

That difference between main clause and subordinate clause is very important in Swedish.

No. Here rätt means correct.

So:

• kundnumret är rätt = the customer number is correct

Swedish rätt can mean different things depending on context:

• correct: Det är rätt.
• right-hand side / right direction: till höger is more common for direction
• law / legal right in some contexts: rätt
• dish/course in food contexts: en rätt

In this sentence, it clearly means correct.

Because Swedish usually expresses definiteness by adding an ending to the noun:

• simkortet = the SIM card
• kundnumret = the customer number

So Swedish does not need a separate word like the in these cases.

This is one of the biggest structural differences from English.

Here it is capitalized simply because it is the first word of the sentence.

In modern Swedish, du is normally written with a lowercase d in the middle of a sentence, even when addressing someone politely.

So:

• Du kan aktivera simkortet... at the start of a sentence
• ... om du vill in the middle of a sentence

Unlike German, Swedish does not normally capitalize the polite you in everyday standard writing.

Swedish kan covers both ideas:

• can
• is able to

Depending on context, it may also sound like may in practical instructions, especially where English might say you can to mean it is possible to.

So in this sentence, Du kan aktivera simkortet... means something like:

• You can activate the SIM card
• You are able to activate the SIM card
• It is possible to activate the SIM card

The exact nuance depends on the situation.

Because Swedish often uses adjectives or predicate words more directly than English does.

• kundnumret är rätt literally looks like the customer number is correct

That is the natural Swedish way to say it. Swedish does not need to say something like the correct one here.

This kind of structure is very common:

• Adressen är fel. = The address is wrong.
• Numret är rätt. = The number is correct.

Yes, but the nuance changes a little.

• Du kan aktivera simkortet om kundnumret är rätt.
• Du kan aktivera simkortet förutsatt att kundnumret är rätt.

Both are possible, but förutsatt att sounds more explicit and formal, like provided that.
Om is more general and often more conversational.

So if this is from a website, instructions, or customer support text, förutsatt att is very natural.

A learner often wonders where the stress goes. In both words, the main stress is usually on the first part:

• SIM-kortet
• KUND-numret

A rough pronunciation guide:

• simkortet ≈ SIM-kor-tet
• kundnumret ≈ KUND-num-ret

A few useful points:

• sj, tj, and other tricky Swedish sounds do not appear here, so these words are relatively straightforward.
• The final -et in simkortet is pronounced clearly.
• In kundnumret, the middle part is reduced compared with the full spelling nummer.

Yes. Swedish can move the conditional part to the front:

• Förutsatt att kundnumret är rätt kan du aktivera simkortet.

That is fully correct.

Notice the word order in the main clause after the fronted phrase:

• kan du
• not du kan

This is because Swedish follows the V2 rule in main clauses: when something other than the subject comes first, the finite verb usually comes before the subject.

So compare:

• Du kan aktivera simkortet...
• Förutsatt att kundnumret är rätt kan du aktivera simkortet.

It sounds neutral to somewhat formal.

Reasons:

• aktivera is standard written language
• förutsatt att sounds more formal than everyday om
• the whole sentence has the tone of instructions, customer support, or website text

A more casual version might be:

• Du kan aktivera simkortet om kundnumret stämmer.

But the original sentence is very natural in service or informational contexts.