Potrącenie jest wysokie.

Because potrącenie is a neuter noun in Polish, and the adjective has to agree with it in gender, number, and case.

So in the singular nominative:

• masculine: wysoki
• feminine: wysoka
• neuter: wysokie

Since the sentence is Potrącenie jest wysokie, the adjective must be wysokie.

A very common clue is the ending -e in the dictionary form. Many Polish neuter nouns end in:

• -o
• -e
• -ę
• -um (usually loanwords)

Potrącenie ends in -e, so it is neuter.

Also, many nouns ending in -nie / -cie that are formed from verbs are neuter, for example:

• pytanie = question
• jedzenie = food / eating
• potrącenie = deduction / knocking down, depending on context

Jest means is. It is the 3rd person singular form of być = to be.

So:

• Potrącenie = the deduction / the reduction / the knockdown, depending on context
• jest = is
• wysokie = high

In Polish, unlike in Russian for example, you normally do use jest in present-tense sentences like this when you are linking a subject with an adjective:

• On jest zmęczony. = He is tired.
• Cena jest wysoka. = The price is high.
• Potrącenie jest wysokie. = The deduction is high.

In casual speech, jest is sometimes dropped, but that is less neutral and more conversational:

• Potrącenie wysokie.

For a learner, the full version with jest is the safest choice.

In Polish, predicate adjectives usually come after być:

• Cena jest wysoka.
• Dom jest duży.
• Potrącenie jest wysokie.

This is different from an adjective directly describing a noun inside a noun phrase:

• wysokie potrącenie = a high deduction

So compare:

• Potrącenie jest wysokie. = The deduction is high.
• Wysokie potrącenie = a high deduction

Both are correct, but they are used in different sentence structures.

It is in the nominative case, because it is the subject of the sentence.

The adjective wysokie is also in the nominative singular neuter form, because it agrees with potrącenie.

This is a very typical pattern:

• subject in nominative
• jest
• adjective agreeing with the subject

For example:

• Dziecko jest małe. = The child is small.
• Auto jest nowe. = The car is new.
• Potrącenie jest wysokie. = The deduction is high.

Yes, but like English high, Polish wysoki / wysoka / wysokie is often used not only for physical height, but also for amounts, levels, prices, fees, and similar things.

So it can mean:

• physically tall/high
• numerically high
• large in amount

That is why it works naturally with things like:

• wysoka cena = a high price
• wysoki podatek = a high tax
• wysokie potrącenie = a high deduction

A native English speaker may expect big, but Polish often prefers wysoki/wysoka/wysokie for amounts.

Sometimes, but wysokie is usually better for amounts, charges, deductions, taxes, prices, and percentages.

Compare the nuance:

• wysokie potrącenie = high deduction, more standard for an amount
• duże potrącenie = large deduction, possible, but often less idiomatic depending on context

Polish commonly uses wysoki for things that can be measured on a scale:

• wysoka pensja = high salary
• wysokie koszty = high costs
• wysokie oprocentowanie = high interest rate

So wysokie is a very natural choice here.

Yes. This is an important vocabulary point.

Depending on context, potrącenie can mean things such as:

• a deduction or withholding from money
• a legal/financial set-off
• a knocking down or striking someone/something, especially by a vehicle

So the sentence Potrącenie jest wysokie may sound natural in a financial context if the meaning is The deduction is high.

In a traffic-accident sense, wysokie would be less obvious unless the context makes clear what is being measured, so learners should rely on the surrounding situation.

A simple learner-friendly approximation is:

po-TRON-tse-nye yest vi-SO-kye

A few notes:

• ą is a nasal vowel; before c it often sounds close to on
• c is pronounced like ts
• nie at the end sounds roughly like nye
• w in Polish sounds like English v
• j sounds like English y

So:

• Potrącenie ≈ po-TRON-tse-nye
• jest ≈ yest
• wysokie ≈ vi-SO-kye

Yes, it is grammatically natural and clear, especially in a formal or neutral context.

It sounds like the kind of sentence you might see or hear in:

• payroll
• accounting
• banking
• legal or administrative language

If the context is financial, it is very normal.

A speaker might also phrase the idea in other ways depending on style, for example:

• To potrącenie jest wysokie. = This deduction is high.
• Potrącenie było wysokie. = The deduction was high.
• Wysokość potrącenia jest duża. = The amount of the deduction is large.

But your sentence is fully correct and natural.