دانستن dânestan: to Know | Farsi Grammar

دانستن dânestan means “know” primarily when the knowledge is a fact, an answer, or a proposition. Its past stem is دانستـ dânest- and its present stem is دانـ dân-: می‌دانم “I know,” دانستم “I knew/found out,” and بدانم “that I know/may know.”

English uses know for facts, people, places, skills, and ability. Persian divides those meanings. دانستن handles facts; شناختن handles familiarity with people and places; بلد بودن handles learned practical know-how in everyday Iranian Persian; and توانستن expresses actual ability. This lexical split is more important than the conjugation table.

Principal parts and high-value paradigm

Item	Persian	Reading	Register or use
infinitive	دانستن	dânestan	to know
past stem	دانستـ	dânest-	دانستم، می‌دانستم
present stem	دانـ	dân-	می‌دانم، بدانم
past participle	دانسته	dâneste	perfect; also “knowingly/known” in compounds
imperative	بدان؛ بدانید	be-dân; be-dânid	formal/literary “know, be aware”
negative imperative	ندان؛ ندانید	na-dân; na-dânid	rare, literary or rhetorical

Person	Present indicative	Simple past	Present perfect	Present subjunctive
I	می‌دانم	دانستم	دانسته‌ام	بدانم
you (sg.)	می‌دانی	دانستی	دانسته‌ای	بدانی
he/she/it	می‌داند	دانست	دانسته است	بداند
we	می‌دانیم	دانستیم	دانسته‌ایم	بدانیم
you (pl./polite)	می‌دانید	دانستید	دانسته‌اید	بدانید
they	می‌دانند	دانستند	دانسته‌اند	بدانند

The regular negative forms are نمی‌دانم، ندانستم، ندانسته‌ام، ندانم. For an ongoing state in the past, everyday Persian normally uses imperfective می‌دانستم “I knew,” not perfective دانستم. Simple دانستم often presents a boundary: “I learned, realized, came to know,” and can sound formal or narrative.

نشانی دقیق اداره را نمی‌دانم، اما شماره‌ی تلفنش را دارم.

neshâni-ye daqiq-e edâre râ nemi-dânam, ammâ shomâre-ye telefon-ash râ dâram.

I don’t know the office’s exact address, but I have its phone number. (neutral standard; known-information object)

از روی پیامش دانستم که جلسه لغو شده است.

az ru-ye payâm-ash dânestam ke jalase laghv shode ast.

From her message, I learned that the meeting had been canceled. (formal-neutral narrative; bounded دانستم)

آن موقع نمی‌دانستیم قطار در ایستگاه بعدی توقف نمی‌کند.

ân moqe' nemi-dânestim qatâr dar istgâh-e ba'di tavaqqof nemi-konad.

At that time, we didn’t know that the train does not stop at the next station. (neutral; ongoing past state)

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Use دانستم when knowledge is acquired at a point in the story; use می‌دانستم when it was already a continuing state. English simple “knew” often corresponds to Persian می‌دانستم.

Objects and factive complement clauses

An answer, name, address, reason, or other item of information can be a direct object: جواب را می‌دانم. A whole proposition normally follows که. In affirmative می‌دانم که..., the speaker presents the complement as true, so an ordinary factual complement normally uses the indicative, not a subjunctive copied from English uncertainty. The wider clause pattern is covered on Finite Complement Clauses with که.

می‌دانم که فروشگاه جمعه‌ها زودتر بسته می‌شود.

mi-dânam ke forushgâh jom'e-hâ zud-tar baste mi-shavad.

I know that the shop closes earlier on Fridays. (neutral standard; factual که-clause)

نمی‌دانم آیا برای این برنامه هنوز جا هست یا نه.

nemi-dânam âyâ barâ-ye in barnâme hanuz jâ hast yâ na.

I don’t know whether there is still room in this program. (neutral standard; uncertain yes/no complement)

Persian can omit a recoverable object: نمی‌دانم by itself is the complete everyday answer “I don’t know.” It can also soften disagreement by presenting the speaker’s position as uncertainty rather than blunt rejection.

نمی‌دانم؛ شاید بهتر باشد اول با خود سارا صحبت کنیم.

nemi-dânam; shâyad behtar bâshad avval bâ khod-e sârâ sohbat konim.

I’m not sure; perhaps we should speak with Sara herself first. (polite conversational standard)

دانستن versus شناختن, بلد بودن, and توانستن

Use شناختن for acquaintance or familiarity: او را می‌شناسم “I know him,” این محله را می‌شناسم “I know this neighborhood.” Use بلد بودن (neutral/informal) for a practiced skill or knowing how to perform a procedure: رانندگی بلدم “I know how to drive.” Use توانستن when circumstances or capacity make an action possible: می‌توانم رانندگی کنم “I can drive.”

لیلا را از دانشگاه می‌شناسم، ولی خانواده‌اش را نمی‌شناسم.

leylâ râ az dâneshgâh mi-shenâsam, vali khânevâde-ash râ nemi-shenâsam.

I know Leila from university, but I don’t know her family. (neutral standard; personal familiarity with شناختن)

راه‌اندازی دستگاه را بلدم، اما امروز نمی‌توانم کمکتان کنم.

râh-andâzi-ye dastgâh râ balad-am, ammâ emruz nemi-tavânam komak-etân konam.

I know how to start the machine, but I cannot help you today. (neutral; learned skill versus present ability)

می‌دانم چطور/چگونه... is also grammatical “I know how...,” because the following clause states the procedure: می‌دانم چطور تنظیمش کنم. What Persian does not normally do is use دانستن alone as a general modal “can.”

Formal predicative and imperative uses

The frame چیزی را چیزی دانستن means “consider/regard something as something” (formal/academic). It extends “know” to a judgment. Command بدان and plural/polite بدانید mean “know this, be aware” and commonly introduce که in formal exposition, speeches, and literary address. In everyday conversation, یادت باشد or حواست باشد is usually more natural.

پژوهشگران این تفاوت را از نظر آماری معنادار می‌دانند.

pazhuheshgarân in tafâvot râ az nazar-e âmâri ma'nâdâr mi-dânand.

The researchers consider this difference statistically significant. (academic; predicative دانستن)

بدانید که ثبت درخواست به معنی پذیرش آن نیست.

be-dânid ke sabt-e darkhâst be ma'ni-ye paziresh-e ân nist.

Be aware that registering an application does not mean it has been accepted. (formal notice)

Tehran speech

Everyday Tehran changes â before n to u and reduces endings: می‌دونم، می‌دونی، می‌دونه، می‌دونیم، می‌دونین، می‌دونن (informal, regional: Tehran). Negative نمی‌دونم is exceptionally frequent. Standard writing keeps می‌دانم even when dialogue pronunciation is colloquial.

نمی‌دونم کلیدا رو کجا گذاشتم؛ تو ندیدی‌شون؟

nemi-dunam kelid-â ro kojâ gozâshtam; to na-didi-shun?

I don’t know where I put the keys; didn’t you see them? (informal, regional: Tehran)

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Keep the whole register bundle coherent: standard نمی‌دانم کلیدها را کجا گذاشته‌ام and Tehran نمی‌دونم کلیدا رو کجا گذاشتم are both natural, but mixing isolated pieces produces an unstable style.

Common Mistakes

1. Using دانستن for acquaintance with a person

❌ من همکار جدید سارا را می‌دانم.

Incorrect for personal acquaintance — Persian uses شناختن for knowing a person.

✅ من همکار جدید سارا را از جلسه‌ی هفته‌ی پیش می‌شناسم.

man hamkâr-e jadid-e sârâ râ az jalase-ye hafte-ye pish mi-shenâsam.

I know Sara’s new colleague from last week’s meeting.

2. Using دانستن alone for a practical skill

❌ من می‌دانم رانندگی.

Incorrect — this is an incomplete دانستن predicate; everyday Iranian Persian uses بلد بودن for the intended skill meaning.

✅ من رانندگی بلدم، ولی شب‌ها ترجیح می‌دهم رانندگی نکنم.

man rânandegi balad-am, vali shab-hâ tarjih mi-daham rânandegi na-konam.

I know how to drive, but I prefer not to drive at night.

3. Putting a factual complement in the subjunctive

❌ می‌دانم که جلسه فردا باشد.

Incorrect for asserted knowledge — a factual present complement takes an indicative copula.

✅ می‌دانم که جلسه‌ی بعدی فردا صبح است.

mi-dânam ke jalase-ye ba'di fardâ sobh ast.

I know that the next meeting is tomorrow morning.

4. Separating the imperfective prefix

❌ هیچ‌کس جواب دقیق را نمی داند.

Incorrect standard orthography — نمی‌ attaches to داند with a ZWNJ.

✅ هنوز هیچ‌کس دلیل دقیق این تغییر را نمی‌داند.

hanuz hich-kas dalil-e daqiq-e in taghyir râ nemi-dânad.

No one yet knows the exact reason for this change.

Key Takeaways

Memorize دانستن — دانست — دان — دانسته; ordinary present knowledge is می‌دانم.
Use دانستن for facts and propositions, شناختن for familiarity, بلد بودن for learned skills, and توانستن for ability.
می‌دانستم usually means ongoing past “knew”; bounded دانستم often means “learned/realized.”
بدان/بدانید and predicative چیزی را چیزی دانستن are formal or literary.
Tehran می‌دونم is natural speech, but standard prose keeps می‌دانم.

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