English has a sprawling modal system — can, could, may, might, must, have to, should, ought to, need to, be allowed to — and learners often assume Romanian must be just as crowded. It isn't. English's whole "modal soup" boils down to a handful of Romanian verbs, each with a clear job, and the real skill is matching each English modal to the right one — then remembering that nearly all of them govern a să-clause (the conjunctiv), not an infinitive. This page pulls the modals together, sorts them by the meaning they carry, and drills the choice. It assumes you've met the individual verbs already; here we practise picking between them under pressure.
The map: English modal → Romanian verb
| Meaning | English modals | Romanian | Pattern |
|---|---|---|---|
| ability / permission | can, could, may | a putea | pot să + verb (or short inf.) |
| obligation | must, have to | a trebui (invariable trebuie) | trebuie să + verb |
| advice | should, ought to | ar trebui (invariable) | ar trebui să + verb |
| permission (strict) | be allowed to, may | a avea voie | am voie să + verb |
| need (an action) | need to | a avea nevoie să / a trebui să | am nevoie să + verb |
| need (a thing) | need | a-i trebui / a avea nevoie de | îmi trebuie + noun |
| possibility | might, could, may | s-ar putea / se poate | s-ar putea să + verb |
Read the rightmost column and one fact jumps out: almost everything ends in să + a conjugated verb. The infinitive is wrong after these (the single exception is a putea, which also tolerates a bare short infinitive: pot pleca = pot să plec). So the skeleton of nearly every modal sentence is [modal] + să + [conjugated verb] — and the person of the action lives in that second verb, not in the modal.
Possibility: a putea vs s-ar putea
A putea (personal: pot, poți, poate...) is "can / be able." Its impersonal conditional s-ar putea să is "might / could" — a hedged possibility (the full gradient is on the possibility page). The contrast learners must feel: pot să vin ("I can come," I'm able/willing) vs s-ar putea să vin ("I might come," I'm not sure).
Pot să te ajut acum, sunt liber.
I can help you now, I'm free.
S-ar putea să întârzii, e mult trafic.
I might be late, there's a lot of traffic.
Poți să mă suni oricând după ora cinci.
You can call me anytime after five.
Necessity: trebuie să (must) vs ar trebui să (should)
This is the highest-value distinction on the page. Trebuie să is the blunt "must / have to"; its conditional ar trebui să is the soft "should / ought to" (drilled on the should and ought page). Both are invariable — never conjugated for person. The difference is force, not tense.
Trebuie să-mi reînnoiesc pașaportul luna asta.
I have to renew my passport this month.
Ar trebui să-ți reînnoiești pașaportul, expiră curând.
You should renew your passport, it expires soon.
Trebuie să fie acasă, are luminile aprinse.
He must be home, his lights are on. (deduction, not obligation)
That last one shows trebuie doing what English "must" also does — logical deduction ("he must be home"). Same word, ability-of-inference reading, signalled by a stative verb (să fie) after it.
Permission: a avea voie vs a putea
For permission, a putea and a avea voie overlap, but a avea voie ("be allowed") is unambiguous, while a putea shares its form with ability (covered on permission and prohibition). When the rules are the point, choose a avea voie.
Ai voie să folosești dicționarul la examen?
Are you allowed to use the dictionary in the exam?
N-am voie să mănânc dulciuri, sunt diabetic.
I'm not allowed to eat sweets, I'm diabetic.
Need: a avea nevoie / a-i trebui
English "need" splits in Romanian along the action/thing line. To need to do something: a avea nevoie să or simply trebuie să. To need a thing: a avea nevoie de + noun, or the dative îmi trebuie + noun (see a avea nevoie). The de before a noun is obligatory and easy to drop.
Am nevoie să vorbesc cu tine între patru ochi.
I need to talk to you in private. (need + action)
Am nevoie de o pauză, lucrez de dimineață.
I need a break, I've been working since morning. (need + thing, with de)
Îți trebuie o viză ca să intri în țară?
Do you need a visa to enter the country? (îmi trebuie + thing)
Reading the choice: a worked walkthrough
Take an English sentence and locate the meaning before you pick the verb. "You might need to leave early, but you should ask first; you're not allowed to just go." Map each modal:
- might need to → possibility + need + action → s-ar putea să fie nevoie să (or, more naturally, s-ar putea să trebuiască să)
- should → advice → ar trebui să
- not allowed to → strict permission, negated → n-ai voie să
S-ar putea să trebuiască să pleci mai devreme, dar ar trebui să întrebi întâi — n-ai voie să pleci pur și simplu.
You might need to leave early, but you should ask first — you're not allowed to just leave.
Every clause ends in să + a conjugated verb, and not one modal is in the infinitive. That's the shape to internalise.
Drills: pick the right modal
Cover the answers and choose the Romanian frame for each English modal before checking.
1. "I must finish this today." (hard obligation)
Trebuie să termin asta azi.
I must finish this today.
2. "You should call your mother." (advice)
Ar trebui să-ți suni mama.
You should call your mother.
3. "Can I open the window?" (asking permission)
Pot să deschid geamul? / Am voie să deschid geamul?
Can I / Am I allowed to open the window?
4. "It might snow tonight." (possibility)
S-ar putea să ningă diseară.
It might snow tonight.
5. "We need to leave now." (need + action)
Trebuie să plecăm acum. / Avem nevoie să plecăm acum.
We need to leave now.
6. "Children aren't allowed in here." (strict prohibition)
Copiii n-au voie aici.
Children aren't allowed in here.
If you reached for să + a conjugated verb each time, and matched the meaning rather than translating the English word, you've got the system.
Common Mistakes
❌ Eu trebuiesc să plec. / Noi trebuim să mergem.
Incorrect — trebuie is invariable; there's no first-person or plural form. The person sits in the să-verb.
✅ Trebuie să plec. / Trebuie să mergem.
I have to leave. / We have to go.
❌ Pot deschide geamul? (when you mean 'am I permitted')
Ambiguous — reads as 'am I able'. For unmistakable permission use a avea voie.
✅ Am voie să deschid geamul?
Am I allowed to open the window?
❌ Trebuie să plec. (intending gentle advice 'you should go')
Too blunt for advice — that's 'must'. For 'should' use the conditional ar trebui.
✅ Ar trebui să pleci.
You should go.
❌ Am nevoie un sfat.
Incorrect — 'need a thing' takes de: am nevoie DE un sfat.
✅ Am nevoie de un sfat.
I need a piece of advice.
❌ S-ar putea a ploua.
Incorrect — s-ar putea governs a să-clause, never an infinitive.
✅ S-ar putea să plouă.
It might rain.
Key Takeaways
- English's many modals map onto a few Romanian verbs — match the meaning, not the English word.
- a putea = can/may (ability + permission); trebuie să = must (invariable); ar trebui să = should (invariable); a avea voie = be allowed; s-ar putea să = might.
- "Need" splits: a avea nevoie să / trebuie să for an action, a avea nevoie de / îmi trebuie
- noun for a thing.
- Almost every modal governs a să-clause with a conjugated verb — only a putea also allows a bare short infinitive.
- Trebuie and ar trebui never conjugate for person; the person always lives in the să-verb.
Now practice Romanian
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Start learning Romanian→Related Topics
- Conjunctiv After Modals: a putea, a trebui, a vreaA2 — How modal and control verbs (a vrea, a putea, a trebui, a încerca, a reuși, a spera) force a să-clause where English uses an infinitive, and the one verb that still tolerates the infinitive.
- Expressing Need (a avea nevoie de, a-i trebui)A2 — Romanian's two ways to say 'need' — a avea nevoie de + noun (Am nevoie de ajutor) and the dative a-i trebui (Îmi trebuie timp) where the thing needed is the subject — plus a avea nevoie să / trebuie să for 'need to', the impersonal e nevoie să, and why there's no infinitive.
- Expressing Should and Ought (ar trebui, ar fi bine)B1 — How Romanian softens obligation into advice — the conditional ar trebui să ('you should') against the blunt indicative trebuie să ('you must'), the alternatives ar fi bine să / e bine să / ai face bine să, and the stacked past ar fi trebuit să ('should have').
- Permission and Prohibition (a avea voie, e interzis)B1 — How Romanian grants and refuses permission — a avea voie (să) as the unambiguous 'be allowed', se poate? for 'may I?', the prohibition frames e interzis / nu e voie, a lăsa pe cineva să for 'let', and why a putea covers both ability and permission like English 'can'.
- Modal Verbs and Periphrases: ReferenceB1 — A consolidated lookup table mapping every English modal — can, must, should, may, need, want, might — to its Romanian expression and the clause it governs, with the forms, meanings, and the one rule that ties them all together: modal verb + să-clause.