Το πάγιο είναι μικρό.

Το is the definite article here, so it means the.

In this sentence, το πάγιο is the subject: the fixed charge / the standing fee / the plan charge (depending on the meaning you were shown).

A few useful points:

• το is the neuter singular nominative form of the article
• it matches πάγιο, which is also neuter singular
• Greek uses the definite article very often, sometimes more often than English does

So το πάγιο is a complete noun phrase meaning the πάγιο.

In this sentence, πάγιο is a noun and it is the subject of the sentence.

Grammatically, it is:

• neuter
• singular
• nominative case

It is worth knowing that forms like this can sometimes come from adjectives being used as nouns, but in this sentence you should treat το πάγιο as a normal noun phrase.

Είναι is the present-tense form of είμαι, meaning to be.

Here it means is.

So the structure is:

• Το πάγιο = the subject
• είναι = is
• μικρό = small

This is the standard Greek way to make a sentence like X is Y.

Because μικρό has to agree with πάγιο.

Greek adjectives change form to match the noun in:

• gender
• number
• case

Since πάγιο is neuter singular, the adjective must also be neuter singular:

• μικρός = masculine singular
• μικρή = feminine singular
• μικρό = neuter singular

So Το πάγιο είναι μικρό is correct because both the noun and the adjective are neuter singular.

Yes. It is still an adjective.

Here it is a predicate adjective, which means it comes after the verb to be and describes the subject.

So:

• το μικρό πάγιο = the small fixed charge
  
  • adjective directly attached to the noun
• το πάγιο είναι μικρό = the fixed charge is small
  
  • adjective after είναι, describing the subject

Both use the adjective μικρό, but the structure is different.

Yes, Greek word order is more flexible than English word order.

Το πάγιο είναι μικρό is the most neutral, straightforward version.

But other orders are possible for emphasis, for example:

• Μικρό είναι το πάγιο = emphasizes small
• Είναι μικρό το πάγιο = also possible, depending on context

Even when the order changes, the forms still show the relationships between the words.

For a learner, though, Το πάγιο είναι μικρό is the safest basic pattern to use.

Greek does not have an indefinite article like English a/an.

It does have a definite article, like ο, η, το = the.

So Greek can say:

• το πάγιο = the fixed charge
• πάγιο = possibly a fixed charge or just fixed charge, depending on context

In your sentence, the speaker is talking about a specific one, so Greek uses το.

A simple learner-friendly pronunciation is:

• το = toh
• πάγιο = PAH-yo
• είναι = EE-ne
• μικρό = mee-KROH

So the whole sentence sounds roughly like:

toh PAH-yo EE-ne mee-KROH

A few pronunciation notes:

• πάγιο is stressed on the first syllable
• μικρό is stressed on the last syllable
• the accent marks show where the stress goes
• the γ in πάγιο sounds softer than English g

Yes. In Modern Greek, the accent mark shows which syllable gets the stress.

In this sentence:

• πάγιο → stress on πά-
• είναι → stress on εί-
• μικρό → stress on -κρό

If you put the stress in the wrong place, your Greek may sound unnatural, and sometimes it can even create confusion.

So it is a good idea to learn the word together with its accent:

• πάγιο
• είναι
• μικρό

Normally, no. In a standard sentence like this, Greek does use the verb είναι.

So:

• Το πάγιο είναι μικρό = correct, normal sentence

Leaving out είναι would usually sound incomplete or non-standard in ordinary speech.

That is different from some other languages where is can be omitted in the present tense. In Greek, you normally keep it.