I applied through college or university. The process took 1 day. I interviewed at Bain & Company (Princeton, NJ) in Nov 2015
Interview
I applied through on-campus recruiting. Two 30-mn interviews, with 10mn "fit" and 20m mini-case. The cases involved market-sizing questions and some computations (basic maths, but lots of numbers so it could get confusing), but were not very difficult overall.
The people were very friendly and the atmosphere was rather casual.
The interview process was straightforward, two cases interviews in both the first and second rounds. No behavioral questions but you can ask them questions at the end. The only question they ask other than the cases is why office.
First round consist of 2 cases, both had lots of math and interviewers only do the case with the applicant. Also, need to make sure your framework and math are all correct since it’s minimal time.
2 days, 4 interviews total. first day was 2 30 minute and second day was 2 45 minute with higher level employees. All were cases, some more formal than others