Duration with است که | Farsi Grammar

Persian commonly measures an ongoing situation with duration + است که + finite clause: سه سال است که اینجا زندگی می‌کنم “I have lived / have been living here for three years.” The duration is presented as a period that now exists, while the following clause tells you what has been true throughout it.

English normally uses a present perfect or present perfect progressive in this meaning. Persian usually uses است plus an ordinary present-tense clause instead. Copying the English perfect mechanically can therefore obscure the most natural Persian viewpoint.

The ongoing-duration frame

The neutral written and careful-spoken pattern is:

duration expression + است + که + present clause

Time viewpoint	Persian frame	Usual English equivalent
continuing now	سه سال است که کار می‌کنم	I have been working for three years
continuing nonoccurrence	مدتی است که او را ندیده‌ام	I have not seen him/her for a while
continuing at a past reference point	دو سال بود که کار می‌کردم	I had been working for two years
finished interval	سه سال آنجا کار کردم	I worked there for three years

چهار ماه است که برای این شرکت کار می‌کنم.

chahâr mâh ast ke barâ-ye in sherkat kâr mi-konam.

I have been working for this company for four months. (neutral standard; still true now)

یک هفته است که هر روز باران می‌بارد.

yek hafte ast ke har ruz bârân mi-bârad.

It has been raining every day for a week. (neutral standard; continuing pattern)

مدت زیادی است که این مسیر را پیاده می‌روم.

moddat-e ziyâdi ast ke in masir râ piyâde mi-ravam.

I have been walking this route for a long time. (neutral standard)

The present clause is not “less complete” than English have been working. The construction as a whole locates the beginning in the past and asserts continuation to now. Persian distributes that meaning across the duration phrase, است, and the present predicate.

💡

Treat سه سال است که as the viewpoint-setting frame. Once it establishes “from three years ago until now,” the embedded present naturally describes the situation that holds across that interval.

States, activities, and repeated events

The construction accepts a stable state, an ongoing activity, or a repeated event, provided the situation extends through the relevant period. The clause does not have to describe one uninterrupted physical action.

ده سال است که مریم را می‌شناسم.

dah sâl ast ke maryam râ mi-shenâsam.

I have known Maryam for ten years. (neutral; continuing state)

دو ماه است که عصرها کلاس شنا می‌روم.

do mâh ast ke asr-hâ kelâs-e shenâ mi-ravam.

I have been going to swimming lessons in the evenings for two months. (neutral; repeated event)

نیم ساعت است که جلوی سینما منتظرم.

nim sâ'at ast ke jelow-e sinamâ montazer-am.

I have been waiting in front of the cinema for half an hour. (neutral; present state with clitic copula)

In the last example, منتظرم is a present predicate even though it has no می‌. The duration frame works with the kind of present form that the lexical predicate ordinarily requires. Do not add می‌ simply because the situation continues.

Why negative clauses often use the perfect

When the interval measures how long an event has not occurred, Persian often uses a present perfect inside the frame: مدتی است که او را ندیده‌ام. The perfect looks back for the last occurrence, while the outer frame measures the gap up to now.

سه ماه است که خانواده‌ام را ندیده‌ام.

se mâh ast ke khânevâde-am râ na-dide-am.

I haven't seen my family for three months. (neutral; continuing absence of an event)

چند روز است که از نادر خبری نشنیده‌ایم.

chand ruz ast ke az nâder khabari na-shenide-im.

We haven't heard any news from Nader for several days. (neutral)

An ordinary negative present gives a different reading. سه ماه است که جمعه‌ها کار نمی‌کنم describes a repeated current policy: “For three months now, I have not worked on Fridays.” سه ماه است که کار نکرده‌ام instead presents no work event anywhere in the whole interval.

شش هفته است که قهوه نمی‌خورم.

shesh hafte ast ke qahve nemi-khoram.

I haven't been drinking coffee for six weeks. (neutral; continuing habit of abstaining)

This is a genuine aspectual choice, not a mechanical rule that every negative duration requires the perfect. Read more about current relevance on Present Perfect Uses.

Finished time uses a different construction

سه سال است که در شیراز زندگی می‌کنم entails that the residence still continues. To describe a completed stay, Persian normally uses a simple past with the duration as an adverbial: سه سال در شیراز زندگی کردم. Removing است که removes the built-in link to now.

سه سال است که در شیراز زندگی می‌کنم.

se sâl ast ke dar shirâz zendegi mi-konam.

I have been living in Shiraz for three years. (I still live there.)

سه سال در شیراز زندگی کردم و بعد به یزد رفتم.

se sâl dar shirâz zendegi kardam-o ba'd be yazd raftam.

I lived in Shiraz for three years and then moved to Yazd. (finished past interval)

The second sentence is not simply a shorter version of the first. رفتم supplies a later boundary and confirms that the Shiraz period ended. English for three years is compatible with either viewpoint; Persian construction choice makes the contrast clearer.

A duration measured from a past viewpoint

Replace present است with past بود when the measuring point itself is in the past. The following clause commonly uses an imperfective past for a situation that was continuing then.

دو سال بود که در آن مدرسه درس می‌دادم که مدیر عوض شد.

do sâl bud ke dar ân madrese dars mi-dâdam ke modir avaz shod.

I had been teaching at that school for two years when the principal changed. (neutral narrative)

پنج دقیقه بود که منتظر تاکسی بودیم که باران گرفت.

panj daqiqe bud ke montazer-e tâksi budim ke bârân gereft.

We had been waiting for a taxi for five minutes when it started raining. (neutral narrative)

The first که introduces the continuing situation; the second can introduce the event that interrupts or locates it. Repetition is normal and context keeps the roles clear.

Asking how long

Use چند وقت است که ...؟ in neutral conversation and چه مدت است که ...؟ in formal interviews, questionnaires, and careful prose. The answer normally repeats the duration frame.

چند وقت است که در این محله زندگی می‌کنید؟

chand vaqt ast ke dar in mahalle zendegi mi-konid?

How long have you lived in this neighborhood? (polite neutral)

چه مدت است که این نشانه‌ها را دارید؟

che moddat ast ke in neshâne-hâ râ dârid?

How long have you had these symptoms? (formal clinical question)

In informal Tehran speech, است commonly contracts onto the preceding phrase: چند وقته ...؟، دو ساله که .... The spelling below represents that register; use full است in formal prose.

چند وقته اینجا کار می‌کنی؟

chand vaqte injâ kâr mi-koni?

How long have you been working here? (informal, regional: Tehran)

نزدیک به یک ساله که از خونه کار می‌کنم.

nazdik be yek sâle ke az khune kâr mi-konam.

I've been working from home for nearly a year. (informal, regional: Tehran)

💡

In a careful answer, keep the three layers visible: duration یک سال, measuring copula است, and content clause که ... کار می‌کنم. Informal speech can compress the copula, but the same logic remains.

Common Mistakes

1. Copying the English perfect into an ordinary continuing clause

❌ سه سال است که اینجا کار کرده‌ام.

Usually wrong for the intended ‘I have been working here for three years’ — the perfect suggests a completed or result-focused work history rather than the neutral continuing job.

✅ سه سال است که در این درمانگاه کار می‌کنم.

se sâl ast ke dar in darmângâh kâr mi-konam.

I have been working at this clinic for three years.

2. Making است agree with the plural duration noun

❌ چهار ماه هستند که کلاس شروع شده است.

Incorrect — است belongs to the singular duration frame; it does not agree with ماه as a counted noun.

✅ چهار ماه است که کلاس‌های ما شروع شده‌اند.

chahâr mâh ast ke kelâs-hâ-ye mâ shoru' shode-and.

It has been four months since our classes began.

3. Using the infinitive instead of a finite clause

❌ دو ساعت است که منتظر بودن.

Incorrect — the clause after که needs a finite predicate identifying the experiencer.

✅ دو ساعت است که منتظر دوستم هستم.

do sâ'at ast ke montazer-e dust-am hastam.

I have been waiting for my friend for two hours.

4. Using است که for a clearly finished stay

❌ پنج سال است که آنجا کار می‌کنم و پارسال استعفا دادم.

Incorrect time logic — است که ... می‌کنم says the job continues now, but پارسال استعفا دادم says it ended last year.

✅ پنج سال آنجا کار کردم و پارسال استعفا دادم.

panj sâl ânjâ kâr kardam-o pârsâl este'fâ dâdam.

I worked there for five years and resigned last year.

Key Takeaways

duration + است که + present clause normally measures a situation continuing to now.
Persian present often corresponds to English present perfect or present perfect progressive in this frame.
A perfect inside the frame is common when measuring how long an event has not occurred.
Use simple past plus a duration for a finished interval, and بود که for duration measured at a past reference point.
Ask چند وقت است که ...؟ neutrally or چه مدت است که ...؟ formally; informal Tehran often contracts them to چند وقته ...؟.

Now practice Farsi

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Farsi →