When you need to say you have to, should, or need to do something, Brazilian Portuguese gives you a small set of constructions: ter que + infinitive (strong necessity), its near-twin ter de, dever + infinitive (should / ought to), and precisar (de) + infinitive (need to). They overlap, but each carries a different weight of obligation. This page sorts out which to use when, and which one a Brazilian actually says.
Ter que + infinitive: have to
The workhorse of obligation. Ter que + infinitive expresses strong necessity — something you have no real choice about.
| Subject | Ter (present) |
|
|---|---|---|
| eu | tenho | tenho que estudar |
| você / ele / ela | tem | tem que sair |
| a gente | tem | a gente tem que ir |
| nós | temos | temos que ir |
| vocês / eles / elas | têm | têm que pagar |
Eu tenho que estudar hoje, tenho prova amanhã.
I have to study today, I have a test tomorrow.
A gente tem que sair agora ou vai perder o voo.
We have to leave now or we'll miss the flight.
Você tem que ver esse filme, é incrível.
You have to see this movie, it's amazing.
Ter de: the formal twin
Ter de + infinitive means exactly the same thing as ter que. The only difference is register: ter de sounds more formal and written, while ter que dominates everyday speech.
Tenho de sair mais cedo hoje. (formal)
I have to leave earlier today.
O candidato tem de comprovar residência no estado. (formal)
The candidate must prove residence in the state.
Prescriptive grammarians historically preferred ter de, arguing ter que was "incorrect." That battle is long lost: in Brazil, ter que is overwhelmingly the spoken norm and is fully accepted in all but the stiffest formal writing. Use ter que in conversation without hesitation; reserve ter de for formal documents if you want to sound especially polished.
Dever + infinitive: should / ought to
Dever expresses a weaker, moral or expected obligation — closer to English "should" or "ought to" than to "must." It's advice, recommendation, or expectation, not iron necessity. Note that dever takes no preposition — the infinitive follows directly.
Você deve estudar mais se quer passar.
You should study more if you want to pass.
A gente deve respeitar os mais velhos.
We ought to respect our elders.
Dever has a second, distinct use: probability/supposition ("must be," in the deductive sense). Same verb, context decides.
Ele não atende — deve estar dormindo.
He's not answering — he must be sleeping.
Devo chegar às 9, o trânsito tá tranquilo.
I should get there at 9, traffic's light.
That last example shows the everyday probabilistic dever: not "I'm obligated to arrive at 9" but "I'll probably arrive around 9." Brazilians use dever this way constantly for soft predictions. Note the crase in às 9 — a (at) + as (the hours) contract to às.
Precisar (de) + infinitive: need to
Precisar + infinitive means "to need to." Here's the wrinkle: when precisar is followed by a noun, it takes de (preciso de ajuda = I need help). But when followed by an infinitive, the de is normally dropped in Brazilian Portuguese.
Preciso comprar pão antes que a padaria feche.
I need to buy bread before the bakery closes.
Você precisa descansar, tá com cara de cansado.
You need to rest, you look tired.
Preciso de um tempo pra pensar.
I need some time to think.
Compare the first two (infinitive, no de) with the third (noun, with de). Both preciso comprar and preciso de comprar are heard, but preciso comprar (no de) is the strong Brazilian norm with infinitives.
Strength of obligation: a ladder
| Construction | Force | English | Register |
|---|---|---|---|
| ter que + inf. | strong necessity | have to / must | (informal) everyday |
| ter de + inf. | strong necessity | have to / must | (formal) / written |
| precisar + inf. | need | need to | neutral |
| dever + inf. | moral/expected; advice | should / ought to | neutral |
The key contrast for learners: dever is should (advice you could ignore), ter que is must (necessity you can't). "Você deve estudar" is a recommendation; "Você tem que estudar" is non-negotiable.
How this differs from English
English distributes obligation across modal verbs — must, have to, should, ought to, need to — that don't conjugate and never take "to" in odd places. Portuguese uses ordinary verbs that fully conjugate (tenho, tem, têm, tive, terei...) plus a linking word: ter que, precisar (with or without de), and dever with nothing. The hardest part for English speakers is remembering which construction links with que, which with de, and which with no preposition at all. There's no shortcut beyond practice — but the table above is your map.
Spanish speakers have tener que (= ter que) and deber (= dever) as direct parallels, which helps enormously; the main adjustment is the Brazilian preference for ter que over ter de, and dropping de after precisar before infinitives.
Common Mistakes
❌ Eu tenho estudar hoje.
Incorrect — 'ter' obligation needs 'que' (or 'de'): tenho que estudar.
✅ Eu tenho que estudar hoje.
I have to study today.
❌ Você deve de estudar mais.
Incorrect — 'dever' takes no preposition before the infinitive.
✅ Você deve estudar mais.
You should study more.
❌ Eles tem que pagar a conta.
Incorrect — third-person plural is 'têm' with a circumflex.
✅ Eles têm que pagar a conta.
They have to pay the bill.
❌ Preciso de comprar pão.
Awkward in BR — drop the 'de' before an infinitive: preciso comprar.
✅ Preciso comprar pão.
I need to buy bread.
❌ Devo chegar as 9.
Incorrect — 'at 9 o'clock' needs the crase: às 9.
✅ Devo chegar às 9.
I should get there at 9.
Key Takeaways
- ter que + infinitive = strong "have to / must" — the everyday spoken form. ter de is the formal twin.
- dever + infinitive = "should / ought to" (advice) — and also "must" in the sense of probability (deve estar dormindo). No preposition.
- precisar + infinitive = "need to," with de dropped before infinitives but kept before nouns (preciso de ajuda).
- dever is softer (should), ter que is harder (must).
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Start learning Portuguese→Related Topics
- Periphrastic Verb Constructions: OverviewA1 — A tour of the verb + verb constructions that dominate spoken Brazilian Portuguese, with the key BR vs. European Portuguese contrasts.
- Modal Verb Chains: Posso, Devo, Quero + InfinitivoA2 — How Brazilian Portuguese expresses can, should, want, need, and know-how with a modal verb plus an infinitive — including the 'de' that gostar uniquely requires.
- Present Indicative of TerA1 — How to conjugate ter in Brazilian Portuguese for possession and age, the mandatory tem/têm accent, and the everyday existential 'tem' that replaces há.
- Present Indicative of PoderA1 — How to conjugate poder (can, may, be able to) in the Brazilian Portuguese present, the three meanings it covers, and the everyday 'pode ser'.
- Ir + Infinitivo: The Periphrastic FutureA1 — How to form Brazilian Portuguese's default future with ir plus an infinitive — and why there is no 'a' in between.