Formal:
* คุณอยู่ที่ไหนคะ / คุณอยู่ที่ไหนครับ? (khun yùu thîi nai khā / khun yùu thîi nai khráp?) - This is the most polite way to ask. "khun" means "you" and is used with respect. "khā" is used for female speakers and "khráp" is used for male speakers.
* ท่านอยู่ที่ไหนคะ / ท่านอยู่ที่ไหนครับ? (thân yùu thîi nai khā / thân yùu thîi nai khráp?) - This is even more formal than the previous phrase and can be used when addressing someone of high social standing.
Informal:
* อยู่ไหน? (yùu nai?) - This is the most common and casual way to ask. It literally translates to "where are you?".
* อยู่ที่ไหน? (yùu thîi nai?) - This is slightly more formal than "yùu nai?".
Adding "now" to the question:
* ตอนนี้ คุณอยู่ที่ไหนคะ / คุณอยู่ที่ไหนครับ? (dɔan níi khun yùu thîi nai khā / khun yùu thîi nai khráp?) - This means "Where are you now?".
* ตอนนี้ อยู่ที่ไหน? (dɔan níi yùu thîi nai?) - This means "Where are you now?" in a more informal tone.
Other variations:
* คุณอยู่ที่ไหนตอนนี้? (khun yùu thîi nai dɔan níi?) - This also means "Where are you now?".
* คุณอยู่ที่ไหนในตอนนี้? (khun yùu thîi nai nai dɔan níi?) - This is another way to say "Where are you now?".
Note: The choice of which phrase to use depends on the context and your relationship with the person you are speaking to.