Ofis kaçıncı katta?

Kaç means how many / how much.

Kaçıncı means which number / what ordinal number, so in this sentence it means which floor number or what floor.

Compare:

• Kaç kat var? = How many floors are there?
• Ofis kaçıncı katta? = What floor is the office on?

So kaçıncı is used when you want an answer like first, second, third, fourth, not just a quantity.

Because Turkish uses the locative case to express in / on / at.

• kat = floor
• katta = on the floor / on a floor

So Ofis kaçıncı katta? literally means something like:

The office is on which floor?

Without the locative ending, the sentence would sound incomplete or unnatural here.

This is because of consonant harmony.

The locative ending has four common shapes:

• -da
• -de
• -ta
• -te

After a voiceless consonant like t, Turkish uses -ta / -te.

Since kat ends in t, you get:

• kat + ta = katta

So katta is the correct form.

Because the word kat already ends in t, and the locative suffix here begins with t:

• kat
• -ta

When they come together, they are written as katta.

This is normal in Turkish spelling. It is not a separate grammar rule beyond the word and suffix meeting each other.

In Turkish, the present-tense to be is often not expressed with a separate word the way it is in English.

So:

• Ofis kaçıncı katta?

already means

• What floor is the office on?

A literal word-for-word structure is closer to:

• Office which-numbered floor-on?

Turkish often leaves out the equivalent of is in simple present statements and questions like this.

Because this is a wh-question, not a yes/no question.

Turkish uses mi / mı / mu / mü mainly for yes/no questions:

• Ofis katta mı? = Is the office on the floor? / Is the office upstairs? depending on context

But when the question already contains a question word like kaçıncı, you do not use mi:

• Ofis kaçıncı katta? = What floor is the office on?

So the sentence is complete without mi.

Yes, but it is very normal Turkish word order.

The sentence is:

• Ofis = the office
• kaçıncı katta = on which floor

So the whole sentence is:

• Ofis kaçıncı katta?

Turkish often puts the question expression right before the implied predicate area, and the overall order can feel different from English. English says:

• What floor is the office on?

Turkish says more literally:

• The office [is] on which floor?

That word order is natural in Turkish.

Yes. Ofis hangi katta? is also natural and means almost the same thing: Which floor is the office on?

The difference is:

• kaçıncı katta focuses on the number/order of the floor
• hangi katta means which floor more generally

In many everyday situations, they are interchangeable. But kaçıncı katta is especially appropriate when floors are numbered: first, second, third, and so on.

Turkish does not use articles like English a and the in the same way.

So ofis can mean:

• the office
• an office

The exact meaning depends on context. In this sentence, English usually translates it as the office, but Turkish does not need a separate word for that.

A rough guide:

• kaçıncı ≈ ka-chun-juh
• katta ≈ kaht-tah

A few helpful points:

• ç sounds like ch
• c in Turkish usually sounds like English j
• ı is a vowel that does not exist in English; it is a relaxed, unrounded vowel, somewhat like the second vowel in sofa, but not exactly
• tt is pronounced clearly as a doubled t

So try something like:

• Ofis kaçıncı katta?
• oh-fees ka-chun-juh kaht-tah?

No, that would not be correct in standard Turkish for this meaning.

If you want to ask What floor is the office on?, you need the locative form:

• katta

So the correct sentence is:

• Ofis kaçıncı katta?

This is because the meaning is not just which floor, but on which floor.

A useful breakdown is:

• ofis = office
• kaçıncı = which-numbered / what ordinal number
• katta = on the floor

So a very literal translation is:

• The office [is] on which-numbered floor?

Natural English:

• What floor is the office on?