il faut / je dois / je peux: which one?
Three different verbs, three jobs: il faut (impersonal obligation, one single form — je faut does not exist), devoir (someone's own obligation, fully conjugated) and pouvoir (ability, permission, requests). Plus three traps: il ne faut pas means “must not”, not “need not”; savoir ≠ pouvoir; and how to avoid il faut que + subjunctive.
🎯 This page answers one question: faut, doit or peut — which one right now? For all seven ways of expressing obligation (avoir à, être obligé de, il faut que + subjunctive, the strength scale), see “Expressing obligation”; for savoir vs connaître, see that page.
📐 One line each
| What you mean | Use | Why |
|---|---|---|
| Everyone has to (rule, notice) | il faut | impersonal — the subject is always il |
| I have to (it's on me) | je dois | a named subject, fully conjugated |
| I can / may I | je peux | ability, permission, requests |
- Il faut réserver avant 18h. (You have to book before 6 p.m. — everyone)
- Je dois réserver ce soir. (I have to book tonight — my job)
- Je peux réserver pour toi ? (Can I book for you? — a request)
❌
je faut·tu faut·nous fallonsdo not exist. Falloir is an impersonal verb with a single form: il faut / il fallait / il faudra. For “I must”, switch verbs: je dois.
🔁 Two conjugations to memorise
| je | tu | il / elle | nous | vous | ils / elles | |
|---|---|---|---|---|---|---|
| devoir must / should | dois | dois | doit | devons | devez | doivent |
| pouvoir can / may | peux | peux | peut | pouvons | pouvez | peuvent |
| falloir must | — | — | il faut | — | — | — |
🔊 In the singular only the final letter differs (x / x / t) and the three forms sound identical — the subject is what tells you which one. All three verbs take a plain infinitive: il faut partir · je dois partir · je peux partir.
🗣 Everyday sentences
🚦 Rules and notices: il faut
- Il faut arriver à l'heure. (You have to be on time.)
- Il faut du temps. (It takes time — il faut can take a noun too.)
- Il me faut deux heures. (I need two hours — me / te / lui says who needs it.)
📌 Personal obligation: devoir
- Je dois partir maintenant. (I have to go now.)
- On doit rendre ça demain. (This is due tomorrow.)
- Il doit être malade. (He must be ill — devoir also expresses assumption.)
🙋 Requests and ability: pouvoir
- Tu peux répéter, s'il te plaît ? (Could you say that again?)
- Est-ce que je peux entrer ? (May I come in?)
- Je ne peux pas venir ce soir. (I can't come tonight.)
⚡ Three traps
① il ne faut pas = must not, NOT “need not”
- Il ne faut pas fumer ici. = smoking here is forbidden — not “you don't have to smoke”.
- Likewise Tu ne dois pas faire ça. = you must not do that.
To say “you don't have to”:
- Tu n'as pas besoin de venir.
- Ce n'est pas nécessaire de réserver.
🔑 This is exactly the English must not vs don't have to split, and getting it backwards reverses the whole sentence.
② savoir ≠ pouvoir
| French | Meaning |
|---|---|
| Je sais nager. | I can swim — I learned how; it's a skill |
| Je peux nager aujourd'hui. | I am able to swim today — conditions allow it |
For “I speak French”, say Je sais parler français or simply Je parle français — never je peux.
③ Don't force il faut que
- Il faut que je parte is correct, but que triggers the subjunctive.
- → Je dois partir. Same meaning, available from A1, no risk.
In speech, il faut + infinitive is the safe pattern. To point at someone, say Tu dois partir. Leave the subjunctive for B1 (see “The subjunctive”).
Shortcut
A rule → il faut; a person who has to → dois / doit; a person who can → peux / peut. Falloir has one form only, and il ne faut pas means “must not”.