Deset procent stačí.

Because after numerals like pět, šest, deset and so on, Czech normally uses the counted noun in the genitive plural.

• dictionary form: procento
• genitive plural: procent

So:

• jedno procento
• dvě procenta
• tři procenta
• čtyři procenta
• pět procent
• deset procent

That is why Deset procent is the correct form here.

Procent is in the genitive plural.

The whole phrase deset procent acts as the subject of the sentence, but inside that phrase, the noun after the numeral is still in the form required by deset.

So you can think of it like this:

• deset = the numeral
• procent = genitive plural form required after deset

This is a very common Czech pattern with numbers 5 and above.

Stačí is the 3rd person present tense form of stačit.

The verb stačit means to be enough / to suffice.

So:

• stačím = I am enough / I suffice
• stačíš = you are enough / you suffice
• stačí = he/she/it is enough, or they are enough

In this sentence, English usually translates it as is enough.

In the present tense, stačí is actually the same form for both 3rd person singular and 3rd person plural.

So just from stačí, you cannot tell the number.

That said, Czech often treats expressions like deset procent as a quantity, almost like one amount. In other tenses, you will often see singular-style agreement, for example:

• Deset procent stačilo.

So in practice, learners often understand this kind of phrase as a quantity that is enough.

There actually is a verb here: stačí.

English often uses to be plus an adjective or phrase:

• Ten percent is enough.

But Czech often prefers a single verb:

• Deset procent stačí.

So Czech is not missing anything. The idea of is enough is built into the verb stačit.

Yes. That is also natural Czech.

Both mean the same thing, but the word order changes the emphasis:

• Deset procent stačí. = emphasizes ten percent
• Stačí deset procent. = emphasizes the idea that ten percent is enough

Czech word order is more flexible than English, so changing the order often changes focus, not the core meaning.

Not necessarily. Czech can leave it unstated if the context already makes it clear.

For example, depending on context, it could mean:

• ten percent of the price
• ten percent of the population
• ten percent of the work
• ten percent discount

If you want to be explicit, you can add it:

• Deset procent z ceny stačí.
• Deset procent studentů stačí.

But by itself, Deset procent stačí is perfectly normal if the listener already knows ten percent of what.

A simple pronunciation guide:

• Deset → DEH-set
• procent → PRO-tsent
• stačí → STA-chee

A few useful sound notes:

• c in procent sounds like ts
• č in stačí sounds like ch in check
• í is a long ee sound

Also, Czech stress normally falls on the first syllable of each word:

• DEset
• PROcent
• STAčí

Because Czech does not have articles like English.

So Czech does not directly mark the difference between:

• ten percent
• the ten percent
• a ten percent

The exact meaning depends on context.

That is completely normal in Czech, and learners have to get used to understanding definiteness from the situation rather than from articles.

Yes. In writing, that is very common.

• 10 % stačí.

When read aloud, it is still:

• Deset procent stačí.

So the symbol % is just the written shorthand for procent.