Persian باید normally places an obligation, recommendation, or strong expectation over a finite clause: باید بروم “I must go,” باید صبر کنید “you should wait.” The embedded subjunctive ending—not باید—shows who must perform the action. This is fundamentally different from English must, which behaves like a verb and is followed by a bare infinitive.
This page concentrates on practical obligation and advice. The inferential باید in “she must already have arrived” uses the same word but a different kind of meaning; it is previewed below so you can recognize the contrast.
An invariant modal plus an agreeing verb
باید does not conjugate. Person and number appear on the following present subjunctive, whose formation is covered on Present Subjunctive Formation.
| Subject | Pattern with رفتن | Usual meaning |
|---|---|---|
| I | باید بروم | I must/should go |
| you (singular) | باید بروی | you must/should go |
| he/she | باید برود | he/she must/should go |
| we | باید برویم | we must/should go |
| you (plural/polite) | باید بروید | you must/should go |
| they | باید بروند | they must/should go |
من باید تا ساعت چهار در اداره بمانم.
man bâyad tâ sâ'at-e chahâr dar edâre bemânam.
I have to stay at the office until four. (neutral standard; first-person obligation)
باید نشانی جدیدت را در سامانه ثبت کنی.
bâyad neshâni-ye jadid-at râ dar sâmâne sabt koni.
You need to register your new address in the system. (neutral instruction; singular addressee)
مهمانها باید پیش از یازده اتاق را تحویل بدهند.
mehmân-hâ bâyad pish az yâzdah otâq râ tahvil bedahand.
The guests must check out of the room before eleven. (neutral standard; third-person plural)
An independent subject is optional when context and the ending identify it. It becomes useful for contrast: من باید بمانم، ولی شما میتوانید بروید “I have to stay, but you can go.” An overt noun subject normally stands before باید, though Persian word order can shift it for discourse reasons.
A separate, especially formal or generalizing impersonal pattern uses باید + the bare past stem: باید رفت، باید صبر کرد “one must go, one must wait.” It leaves the responsible person generic and therefore does not combine with an overt personal subject. Once a particular subject is named, use its agreeing subjunctive: همه باید صبر کنند, not همه باید صبر کرد.
Obligation or recommendation?
The grammar does not mechanically separate English must, have to, and should. Context, authority, consequences, and intonation determine the force. A posted rule or deadline makes باید obligatory; friendly advice commonly makes it a recommendation.
برای ورود باید کارت شناسایی نشان بدهید.
barâ-ye vorud bâyad kârt-e shenâsâyi neshân bedahid.
To enter, you must show identification. (formal-neutral requirement)
باید این کافهی کوچک را امتحان کنی؛ قهوهاش عالی است.
bâyad in kâfe-ye kuchek râ emtehân koni; qahve-ash âli ast.
You should try this little café; its coffee is excellent. (informal recommendation in otherwise standard wording)
To soften advice, speakers can add به نظرم “in my opinion,” use بهتر است, or phrase it as a question. Bare باید directed at another adult can sound firm when the speaker has no obvious authority.
Two stems, one prefix slot, one ending
The complement follows the ordinary subjunctive system: present stem plus personal ending, normally with بـ. Thus نوشتن supplies stem نویس in بنویسید, not past stem نوشت. In a compound verb, the light verb carries mood and agreement: تصمیم بگیریم، تماس بگیرید، بررسی کنند. Compounds with کردن commonly omit affirmative بـ in neutral modern Persian.
باید پیش از امضا همهی بندها را با دقت بخوانید.
bâyad pish az emzâ hame-ye band-hâ râ bâ deqqat be-khânid.
You should read every clause carefully before signing. (formal-neutral advice)
باید امروز دربارهی بودجه تصمیم بگیریم.
bâyad emruz darbâre-ye budje tasmim begirim.
We have to decide about the budget today. (neutral standard; compound verb)
نباید is “must not,” not “need not”
Negative نباید places prohibition or strong negative advice over the following event: نباید وارد شوید “you must not enter.” It is not simply باید followed by a negative subjunctive. In the modern construction, negation belongs to the modal word itself and the following verb is normally affirmative subjunctive.
نباید این دارو را با معدهی خالی بخوری.
na-bâyad in dâru râ bâ me'de-ye khâli be-khori.
You mustn't take this medicine on an empty stomach. (neutral warning)
کارکنان نباید گذرواژهی خود را در اختیار دیگران بگذارند.
kârkonân na-bâyad gozarvâzhe-ye khod râ dar ekhtiyâr-e digarân begozârand.
Employees must not give their password to others. (formal rule)
For “do not have to,” negate necessity instead: لازم نیست بیایی. That sentence leaves coming optional; نباید بیایی forbids it. The distinction is about scope, not politeness.
فردا تعطیل است؛ لازم نیست به شرکت بیایید.
fardâ ta'til ast; lâzem nist be sherkat biyâyid.
Tomorrow is a holiday; you don't need to come to the office. (neutral standard; absence of necessity)
Inferential باید: a preview
باید can also express a conclusion based on evidence rather than a duty. With a state, باید خانه باشد can mean “she must be at home”; with a perfect complement, باید رسیده باشد means “she must have arrived.” No one is ordering the subject to be home or to have arrived.
چراغ اتاقش روشن است؛ باید هنوز بیدار باشد.
cherâgh-e otâq-ash rowshan ast; bâyad hanuz bidâr bâshad.
The light in her room is on; she must still be awake. (neutral inference, not obligation)
The surrounding proposition usually disambiguates the reading. At A2, first master باید + present subjunctive for things someone is required or advised to do.
Everyday Tehran speech
In Tehran conversation (informal, regional: Tehran), باید often sounds like bâyad or the reduced bâyas, while subjunctive endings and some stems shorten: بروم → برم، بروید → برین، بگویند → بگن. Because the written guide defaults to standard Iranian Persian, reductions should appear only in explicitly colloquial dialogue.
باید زودتر راه بیفتیم، وگرنه به قطار نمیرسیم.
bâyad zud-tar râh bioftim, vagarne be qatâr nemi-resim.
We'd better set off earlier, or we won't catch the train. (careful conversational standard)
باید الان برم؛ آخرین اتوبوس ساعت ده میاد.
bâyad alân beram; âkharin otobus sâ'at-e dah miyâd.
I have to go now; the last bus comes at ten. (informal, regional: Tehran)
Common Mistakes
1. Conjugating باید
❌ من بایدم فردا بروم.
Incorrect in modern standard Persian — باید is invariant; person is marked on بروم.
✅ من باید فردا برای آزمایش بروم.
man bâyad fardâ barâ-ye âzmâyesh beravam.
I have to go for the test tomorrow.
2. Copying the English bare infinitive
❌ باید زودتر رفتن.
Incorrect — ordinary personal obligation requires a finite subjunctive, not the Persian infinitive.
✅ باید پیش از شروع باران حرکت کنیم.
bâyad pish az shoru'-e bârân harekat konim.
We should leave before the rain starts.
3. Using indicative می after باید
❌ باید هر روز میخوانی.
Incorrect for advice or obligation — the dependent verb should be subjunctive.
✅ باید هر روز چند صفحه بخوانی.
bâyad har ruz chand safhe be-khâni.
You should read a few pages every day.
4. Confusing prohibition with optionality
❌ نباید امروز بیایی.
as ‘you do not need to come today’
Incorrect for optionality — this grammatical sentence means you must not come today.
✅ لازم نیست امروز حضوری بیایی.
lâzem nist emruz hozuri biyâyi.
You don't need to come in person today.
Key Takeaways
- باید is invariant; the following subjunctive marks the responsible subject.
- Context makes باید a requirement or recommendation, while evidence can give it an inferential reading.
- The complement uses the present stem and personal ending; compound verbs carry mood on the light verb.
- نباید + affirmative subjunctive means “must not.” Use لازم نیست for “do not have to.”
Now practice Farsi
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Start learning Farsi →Related Topics
- Present Subjunctive FormationA2 — Form the Persian present subjunctive with بـ, the present stem, and personal endings, including vowel allomorphy, preverbs, compounds, irregulars, and stress.
- Negative Present SubjunctiveA2 — Form the negative Persian subjunctive with stressed نـ instead of بـ, including compounds, lexical preverbs, irregular داشتن, and modal contrasts.
- خواستن plus SubjunctiveA2 — Use lexical خواستن with finite subjunctive complements for same- and different-subject wants, and distinguish clausal wanting from wanting an object.
- لازم است and بهتر استA2 — Express impersonal necessity and advice with لازم است and بهتر است, including optional که, subject expression, negation scope, and register.
- Affirmative Imperative with بA2 — Build familiar singular commands from the Persian present stem, including simple, prefixed, and compound verbs.