I am an Indian Ph.D. student living in Europe at the moment, and one of my research papers has been accepted for a conference in the US.
The conference will be in February 2020, I need to apply for a non-immigrant visa (B1/B2) as soon as possible. However, I need to travel to my home country in December 2019 and I need my passport for that.
How long does the US embassy keep your passport?
Last time I researched this was about 10 years ago and for an (already approved) H4 visa.
It varied a lot: anywhere between one day and 6 weeks depending on the specific consulate and whatever person in the consulate you talk to. At the time many consulates basically made up their rules "on the fly" and any type of confirmed date was happily ignored by the next officer. You can try calling the consulates (which typically cost money) and you may or may not get accurate or useful information.
Case in point: We had a dire emergency and we had confirmed a same day appointment in Amsterdam. We had also confirmation from the consulate that, this is indeed a same day process. We did confirm this through three independent sources, including two lawyers. However, when my wife showed up there the consular officer refused to put the (already approved!) visa in her passport because, "he is underpaid and overworked" .
Things may be better now, but it's not easy to find out.
