Kostnadsoverslaget er høyt.

It is a compound noun:

• kostnad = cost
• overslag = estimate, rough calculation

Together, kostnadsoverslag means cost estimate.

The full form kostnadsoverslaget has -et added at the end, which makes it definite singular:

• et kostnadsoverslag = a cost estimate
• kostnadsoverslaget = the cost estimate

Norwegian very often builds long compound nouns like this.

That -s- is a very common linking element in Norwegian compounds.

So:

• kostnad
  • overslag → kostnadsoverslag

This -s- does not usually have a meaning of its own here. It simply helps connect the two parts in a way that sounds natural in Norwegian. English learners often notice this because English usually keeps the words separate, as in cost estimate.

Because Norwegian usually puts the definite article at the end of the noun.

So instead of saying something like the cost estimate, Norwegian says:

• kostnadsoverslaget

That final -et is doing the job of the.

This is very normal in Norwegian:

• et hus = a house
• huset = the house

Because høyt agrees with the noun’s gender.

The head of the compound is overslag, and overslag is a neuter noun:

• et overslag
• therefore et kostnadsoverslag

When an adjective is used after er like this, it usually agrees with the subject:

• common gender singular: høy
• neuter singular: høyt
• plural: høye

So:

• Kostnaden er høy. = The cost is high.
• Kostnadsoverslaget er høyt. = The cost estimate is high.

Because this adjective is predicative, not attributive.

In this sentence, the adjective comes after er:

• Kostnadsoverslaget er høyt.

Predicative adjectives in Norwegian agree in gender and number, but they do not take the definite form.

Compare:

• et høyt kostnadsoverslag = a high cost estimate
• det høye kostnadsoverslaget = the high cost estimate
• Kostnadsoverslaget er høyt = the cost estimate is high

So even though the noun is definite, høyt is still the correct form here.

Er is the present tense of å være = to be.

So:

• jeg er = I am
• du er = you are
• han/hun er = he/she is
• vi er = we are

In this sentence, er means is.

This is the normal word order for a basic Norwegian statement:

• Subject + verb + complement

So:

• Kostnadsoverslaget = subject
• er = verb
• høyt = complement

This matches English quite closely: The cost estimate is high.

Norwegian is also a V2 language, which means the finite verb normally comes in the second position in main clauses. In this simple sentence, that gives the same order English learners would expect.

Yes, very much so. Norwegian often uses høy / høyt for amounts, prices, levels, and estimates, just like English uses high.

So here høyt means that the estimate is large in amount.

It does not mean physically tall here. The meaning depends on context.

The noun would become:

• et kostnadsoverslag = a cost estimate

So a grammatically parallel sentence would be:

• Et kostnadsoverslag er høyt.

That is correct grammatically, but in real usage it may sound a bit general or abstract unless the context makes it clear which kind of estimate you are talking about.

Most often, people would use the definite form when referring to a specific estimate already known in the conversation:

• Kostnadsoverslaget er høyt.

A rough guide is:

• kost-nahds-OO-ver-slah-get

A few helpful notes:

• å sounds somewhat like the vowel in British thought for many speakers.
• o in kost- is shorter than English learners often expect.
• The -et at the end is usually pronounced lightly.

The exact pronunciation varies by dialect, but the most important thing is to say it as one compound word, not as separate words.

A rough English-friendly guide is:

• hoyt, but with a Norwegian ø sound, not a normal English o

The tricky part is ø. For many English speakers, it is somewhere near the vowel in British bird without the r, though that is only approximate.

Also, øy is a vowel combination, so the word is not pronounced exactly like English height or hoit, even if that may be a useful first approximation.

Yes. Kostnadsestimatet is also possible and means roughly the same thing: the cost estimate.

So you may hear both:

• Kostnadsoverslaget er høyt.
• Kostnadsestimatet er høyt.

Overslag can feel a bit like a rough estimate or calculation, while estimat is closer to the international word estimate. In many contexts, both work fine.