Including overhead I am well over 12 hours/day but pure coding... Really depends on how many times people disturb me with 'stuff'.

I have worked with many freelancers and worked (as tech consultant) in many big and small businesses; a lot of capable tech people, in my experience, vastly understate the time they actually work. When they are in meetings, all day, they feel they didn't work and report hours accordingly. I have to point out to them regularly that even though they reported 3 hours, I was in meetings with them for 6 (and yes, I find that generally quite pointless so I understand the sentiment), so I think it's closer to 8-9 hours.