Mainstream consulting firms generally consider 9 in the morning to 9 at night to be typical “core hours”, with some variations on both sides of the period. On average, the normal number of hours a consultant can expect to work in a week ranges from 70 to 75 hours, including lunch and travel time. However, it depended on the project, because if I dedicated myself to a short 2-week due diligence project, I didn't have a weekend. It's really interesting to work on those projects because you're spending two weeks on whatever you're doing, but it's not a pace you want to maintain for too long.
However, in general terms, it was normally a 60-70 hour work week. MBA jobs at big global consulting firms don't have much easier. MBA at McKinsey & Co. At Boston Consulting Group, they work 63 hours a week, while at Bain & Co.
Bain's numbers may be lower because the company adopts a “home office system” to reduce all travel time.