Roughly 7 miles each way. 6 of it is on a dead flat bike trail. (OK, so there's a couple of dips in the trail where it goes underneath the bridges, but those don't really count as "hills.") The last mile is on a road with good bike lanes for most of it, and the last 0.7 miles is uphill.
I enjoy my commute because on a clear day I have a few miles on the trail with a really great view of Mt. Rainier. I'll enjoy it even more when I get my Bianchi San Jose, instead of the heavy old clunker I'm riding now.