फ्लैट कब से खाली है?

कब से literally means since when. In natural English, this sentence is often understood as How long has the flat been empty?

So in this sentence:

• कब = when
• से = since / from

Together, कब से asks about the starting point of a continuing situation.

In Hindi, से is commonly used to mark a starting point in time.

Compare:

• फ्लैट कब खाली है? → this is not natural Hindi
• फ्लैट कब खाली था? → When was the flat empty?
• फ्लैट कब से खाली है? → Since when has the flat been empty? / How long has the flat been empty?

So कब asks for a time, but कब से asks for the beginning of an ongoing period.

This is a very common point for English speakers.

Hindi often uses the present form of होना (है) with a state that began in the past and continues now, especially when the sentence already includes कब से.

So:

• फ्लैट कब से खाली है?

literally looks like:

• The flat is empty since when?

But the real meaning is:

• How long has the flat been empty?

Hindi does not need a separate structure exactly matching English has been in this kind of sentence.

खाली means empty, but with places like a flat, house, room, shop, or seat, it often means vacant or unoccupied.

So here खाली is best understood as:

• empty
• vacant
• not being used / not occupied

Examples:

• कमरा खाली है। = The room is empty.
• दुकान खाली है। = The shop is vacant / empty.

Hindi word order is usually different from English.

This sentence is:

• फ्लैट = the flat
• कब से = since when
• खाली = empty
• है = is

So the structure is roughly:

• subject + time phrase + description + is

That is normal in Hindi. English prefers:

• How long has the flat been empty?

So even though the meanings match, the word order does not.

It is a very common borrowed word from English, written in Devanagari as फ्लैट.

In modern Hindi, especially in cities, people often use English loanwords like:

• फ्लैट = flat / apartment
• ऑफिस = office
• बस = bus
• ट्रेन = train

So फ्लैट is completely normal in everyday Hindi.

Yes. That is one reason this expression can feel tricky to English speakers.

Depending on context, कब से may invite answers like:

• सोमवार से। = Since Monday.
• दो महीनों से। = For two months.

So in practice, फ्लैट कब से खाली है? can ask either:

• Since when is the flat empty?
• How long has the flat been empty?

Both ideas are very close.

Because खाली is effectively used as an indeclinable adjective here. It does not change to match gender or number in the way some Hindi adjectives do.

Compare with a changeable adjective like बड़ा:

• बड़ा कमरा = big room
• बड़ी मेज़ = big table

But with खाली, you usually just keep खाली:

• कमरा खाली है।
• मेज़ खाली है।
• दुकान खाली है।

So you do not need to worry about changing खाली here.

Yes. That is a very natural alternative.

खाली पड़ा है gives a slightly stronger sense of:

• has been lying empty
• has been sitting vacant

So:

• फ्लैट कब से खाली है? = neutral, simple
• फ्लैट कब से खाली पड़ा है? = emphasizes that it has remained unused or vacant

Both are correct, but खाली पड़ा है sounds a bit more vivid.

A simple pronunciation guide is:

flaiṭ kab se khālī hai?

Approximate sounds:

• फ्लैट = flat / flait
• कब = kub (short u-like sound)
• से = say
• खाली = khaa-lee
  
  • खा has a long aa
  • ख is an aspirated k, like a breathy kh
• है = often sounds like hai or somewhat like heh depending on speaker and region

A natural rhythm would be:

फ्लैट कब से खाली है?
flaiṭ kab se khālī hai?

Usually, the answer gives either a starting point or a duration.

Examples:

• यह फ्लैट सोमवार से खाली है। = This flat has been empty since Monday.
• यह फ्लैट दो महीने से खाली है। = This flat has been empty for two months.
• यह फ्लैट पिछले साल से खाली है। = This flat has been empty since last year.

So when you hear कब से, expect an answer with a time expression.