How many hours/week an average engineer work effectively at big tech?

It’s hard to measure, I live in France and probably work 25 hours a week (out of the regular 35 hours we are supposed to do)

But then I don’t count the many hours reading documentation, practicing and exploring at home and most of the time it’s geared toward « what I can do to improve X at work »

Also my mind is rarely off, there is always part of my brain focused on some challenges we are facing at work.

I don’t know how others do it, but I can’t produce code 7h a day just sitting on my chair

“Yeah, I just stare at my desk; but it looks like I'm working. I do that for probably another hour after lunch, too. I'd say in a given week I probably only do about fifteen minutes of real, actual, work.” :)