Expressing Need, Obligation, and Advice | Polish Grammar

Telling someone they must, should, or need to do something draws on three different Polish systems at once: ordinary modal verbs (muszę), impersonal expressions (trzeba, warto), and the conditional (na twoim miejscu bym…). English packs all of this into a small set of modals — must, should, ought, need to — that barely inflect. Polish spreads the work across verbs that conjugate, a gender-marked "should" form, and impersonals with no subject at all. This page is the phrase bank for the whole territory of necessity and advice, with the one trap that catches every English speaker — nie musisz ≠ "you mustn't" — flagged front and centre.

Muszę — "I must / I have to"

Musieć ("to have to") is the everyday verb of obligation. It conjugates like a normal verb and takes an infinitive: muszę iść ("I have to go"), musisz poczekać ("you have to wait"). It covers both internal compulsion ("I really must call her") and external necessity ("I have to be at work by eight") — Polish does not split these the way some languages do.

Person	Form	Example
ja	muszę	Muszę już iść.
ty	musisz	Musisz odpocząć.
on/ona/ono	musi	Ona musi się uczyć.
my	musimy	Musimy się pospieszyć.
wy	musicie	Musicie to zobaczyć.
oni/one	muszą	Oni muszą poczekać.

Muszę już iść, bo spóźnię się na pociąg.

I have to go now, or I'll miss my train.

Musisz koniecznie spróbować tych pierogów.

You absolutely have to try these dumplings.

W poniedziałek muszę być w pracy o ósmej.

On Monday I have to be at work at eight.

The trap: nie musisz means "you don't have to"

Here is the single most important point on this page. English must and its negation are asymmetric: "you must not" forbids, "you don't have to" releases. Polish nie musieć only carries the releasing meaning. Nie musisz = "you don't have to / you needn't" — never "you mustn't".

Nie musisz dzwonić, napisz mi po prostu wiadomość.

You don't have to call — just text me.

Nie musimy nigdzie iść, możemy zostać w domu.

We don't have to go anywhere, we can stay home.

To actually forbid something — to say "you mustn't / you may not" — Polish reaches for nie wolno (impersonal "it's not allowed"; see moc / wolno / można) or nie powinieneś ("you shouldn't"):

Tu nie wolno parkować.

You mustn't park here. (it's not allowed)

Nie powinieneś tyle pracować.

You shouldn't work so much.

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Memorise the pair: nie musisz = "you don't have to" (permission to skip), nie wolno ci = "you mustn't" (prohibition). An English speaker who says nie musisz palić meaning "you mustn't smoke" has accidentally said "you don't have to smoke" — the opposite of what they intend. To forbid, use nie wolno.

Trzeba — the impersonal "one must / it's necessary"

Trzeba is a subjectless word meaning "it is necessary / one has to". There is no ja, no ty — nobody is named; the obligation hangs in the air, applying to whoever is relevant. It takes an infinitive and is hugely common precisely because it lets you state a necessity without pointing a finger.

Trzeba kupić chleb, skończył się.

We need to buy bread, it's run out. (lit. 'one must buy bread')

Trzeba było zadzwonić wcześniej.

One should have called earlier. (past: trzeba było)

Co trzeba zrobić, żeby tu pracować?

What does one need to do to work here?

Its close cousin warto ("it's worth it") gives soft advice — "it's worth doing" — and is one of the most natural ways to recommend something without an imperative:

Warto zobaczyć Kraków, jest naprawdę piękny.

Kraków is worth seeing, it's really beautiful.

Warto pomyśleć o tym jeszcze raz.

It's worth thinking about this again.

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Trzeba and warto are impersonal — they never agree with a person and never take a subject pronoun. Their only "tense" marker is the neuter było for the past (trzeba było, warto było). For the full impersonal modality system, see musieć vs trzeba.

Powinienem / Powinnam — "I should" (gender-marked)

To say "I should", Polish uses powinien, a strange semi-verb that behaves like an adjective: it agrees with the speaker's gender and takes personal endings. This trips up English speakers because should in English is invariant. A man says powinienem; a woman says powinnam.

Person	Masculine	Feminine
ja	powinienem	powinnam
ty	powinieneś	powinnaś
on / ona	powinien	powinna
my	powinniśmy	powinnyśmy
wy	powinniście	powinnyście
oni / one	powinni	powinny

It takes an infinitive and expresses what is advisable or expected, weaker than muszę (obligation) — exactly the gap English fills with should/ought to.

Powinieneś odpocząć, wyglądasz na zmęczonego.

You should rest, you look tired. (to a man)

Powinnam była zadzwonić, przepraszam.

I should have called, I'm sorry. (woman speaking, past)

Wszyscy powinni nosić maseczki w autobusie.

Everyone should wear masks on the bus.

The past ("should have") adds był/była/było after the form: powinieneś był (m.), powinnaś była (f.) — a doubly gender-marked construction that signals a missed obligation, regret. For the full paradigm and the trzeba/warto/powinien contrast, see musieć vs trzeba vs powinien.

Potrzebuję + genitive — "I need (a thing)"

To say you need a thing (a noun, not an action), use potrzebować, and remember: it governs the genitive case, not the accusative. Potrzebuję pomocy ("I need help" — pomoc → genitive pomocy), potrzebuję czasu ("I need time"). This is one of the highest-frequency genitive-governing verbs in the language.

Potrzebuję twojej pomocy.

I need your help. (pomoc → genitive pomocy)

Potrzebuję więcej czasu, żeby to skończyć.

I need more time to finish this.

Czego potrzebujesz? — Potrzebuję długopisu.

What do you need? — I need a pen. (długopis → genitive długopisu)

When you need to do something (a verb), Polish drops potrzebować and uses muszę + infinitive instead — muszę odpocząć ("I need to rest"), not potrzebuję odpocząć. The latter is a calque that sounds foreign.

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Potrzebować takes the genitive for the thing needed (potrzebuję wody, "I need water"), and answers the question czego? ("of what?"). For "I need to do X", switch to muszę + infinitive. See the verb pairing in musieć / potrzebować and the broader pattern in verbs that take the genitive.

Giving advice: Radzę ci, Na twoim miejscu, Lepiej

When you advise another person, Polish has several softening frames beyond bare powinieneś.

Radzę ci ("I advise you") takes a dative addressee (ci = "to you") plus an infinitive — direct but warm:

Radzę ci odpocząć przed egzaminem.

I advise you to rest before the exam.

Na twoim miejscu ("in your place / if I were you") sets up a conditional — note the bym/byś particle of the conditional mood — and is the gentlest, most native way to give advice:

Na twoim miejscu bym tego nie kupował.

If I were you, I wouldn't buy that. (conditional bym + past-form verb)

Na twoim miejscu poszłabym do lekarza.

If I were you, I'd go to the doctor. (woman advising → poszłabym)

Lepiej ("better") + verb is a compact, very common suggestion — "better to…":

Lepiej weź parasol, ma padać.

Better take an umbrella, it's supposed to rain.

Lepiej zadzwoń do niej teraz, później będzie za późno.

You'd better call her now, it'll be too late later.

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Polish advice climbs a politeness ladder: Musisz… (you must — strong) → Powinieneś… (you should) → Radzę ci… (I advise you) → Lepiej… (better to) → Na twoim miejscu bym… (if I were you — softest). The conditional bym at the bottom is the most face-saving; see the conditional formation.

Mam + infinitive — the obligation you were given

A subtler one: mieć ("to have") + infinitive expresses an obligation imposed by someone else — "I'm (supposed) to…", like English "I'm to call him". It signals an instruction received, not a personal need.

Mam zadzwonić do szefa o trzeciej.

I'm to call the boss at three. (it's what I was told to do)

Co mam zrobić? — Masz tu poczekać.

What am I to do? — You're to wait here.

This mam + infinitive ("I'm supposed to") is distinct from muszę (internal/general necessity) and is worth keeping separate: it always implies an external instruction.

Common Mistakes

Reading nie musisz as "you mustn't". It means "you don't have to". To forbid, use nie wolno.

❌ Nie musisz tu palić. (meaning 'you mustn't smoke here')

Incorrect — this says 'you don't have to smoke here'.

✅ Tu nie wolno palić.

You mustn't smoke here. (it's not allowed)

Using the accusative after potrzebować. This verb takes the genitive.

❌ Potrzebuję pomoc.

Incorrect — potrzebować governs the genitive: pomocy.

✅ Potrzebuję pomocy.

I need help.

Forgetting gender on powinien. A woman says powinnam, not powinienem.

❌ Powinienem zadzwonić. (said by a woman)

Incorrect — a woman says powinnam.

✅ Powinnam zadzwonić.

I should call. (woman speaking)

Calquing "I need to rest" as potrzebuję odpocząć. For a needed action, use muszę + infinitive.

❌ Potrzebuję odpocząć.

Incorrect calque — for a needed action use muszę.

✅ Muszę odpocząć.

I need to rest.

Giving trzeba or warto a subject or a personal ending. They are impersonal — no ja, no agreement; the past is the neuter było.

❌ Ja trzebam kupić chleb.

Incorrect — trzeba is subjectless and never conjugates.

✅ Trzeba kupić chleb.

We need to buy bread.

Key Takeaways

Muszę
- infinitive = "I have to"; conjugates normally; covers both internal and external necessity.
nie musisz = "you don't have to" — NOT "you mustn't". To forbid, use nie wolno or nie powinieneś.
Trzeba / warto are impersonal ("one must" / "it's worth"); no subject, past = trzeba było / warto było.
Powinienem/powinnam = "I should", gender-marked and adjective-like; "should have" adds był/była.
Potrzebuję
- genitive for a needed thing (potrzebuję pomocy); for a needed action use muszę.
Advice softens through Radzę ci… → Lepiej… → the conditional Na twoim miejscu bym….
Mam
- infinitive = an obligation imposed by someone else ("I'm to…").

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