Portionsstorleken är för stor.

It is made up of several parts:

• portion = portion, serving
• -s- = a linking sound used in many compounds
• storlek = size
• -en = the (definite singular ending)

So the whole word is a compound noun meaning the portion size.

Because Swedish normally writes compound nouns as a single word.

So where English often writes:

• portion size
• coffee cup
• school bus

Swedish usually writes:

• portionsstorlek
• kaffekopp
• skolbuss

This is very common in Swedish, and it is something English speakers have to get used to.

That -s- is called a linking s. In Swedish compounds, an s is sometimes inserted between the first and second part of the word.

So:

• portion
  • storlek → portionsstorlek

It does not mean possession here. It is just part of how the compound is formed. Unfortunately, there is no perfectly simple rule for when Swedish uses this linking s, so it is often best to learn each compound as a whole word.

The ending -en marks the definite form, like the in English.

Compare:

• en portionsstorlek = a portion size
• portionsstorleken = the portion size

In Swedish, the definite article is often attached to the end of the noun instead of being a separate word.

Är is the present tense of vara, which means to be.

So:

• är = is / are

In this sentence, it works just like English is.

Examples:

• Han är trött. = He is tired.
• Maten är kall. = The food is cold.

Yes, för can often mean for, but in this sentence it means too.

With adjectives, för + adjective means too ...:

• för stor = too big / too large
• för liten = too small
• för dyr = too expensive

So this is a very common pattern in Swedish.

Because the adjective has to agree with the noun it describes.

Here, portionsstorleken is:

• singular
• common gender (an en word)

So the adjective form is stor.

Compare:

• Portionsstorleken är för stor.
  common gender singular

• Huset är för stort.
  neuter singular

• Portionerna är för stora.
  plural

This is standard adjective agreement after är as well.

Because they are related words:

• stor = big, large
• storlek = size

So the sentence may feel a bit repetitive if you translate it very literally. But this is completely natural in Swedish. It works like saying something such as the size is too large in English.

Swedish often uses stor in this kind of sentence without sounding strange.

Yes, but it means something slightly different.

• Portionsstorleken är för stor focuses on the size of the portion.
• Portionen är för stor focuses on the portion itself.

In many real situations, both are possible. The first sounds a bit more like you are commenting on portion sizing in general, such as in a restaurant, product description, or dietary context.

This sentence has normal Swedish main-clause word order:

• Portionsstorleken = subject
• är = verb
• för stor = complement

So it follows the basic pattern:

subject + verb + complement

That is the most straightforward word order for a simple statement like this.