Yeah kids and commuting eat at least half that. Take another hour off, minimum, for basic chores to make sure you have food and your house doesn't turn into such a disgusting mess that makes the nightly news.

Also all hours aren't created equal and congratulations, you now have what are probably your three—at most—worst hours left to try to "make" in, without cutting into sleep. BTW unlike a job the time commitment is barely better on the weekends. Hope you can work productively while having 1-10 minute interruptions every 1-10 minutes. If not then the math's identical to that for a weekday.