I'm an American planning a Eurotrip from mid January to August 2014. The first 60 days will be spent in the Schengen zone, followed by 90 days outside then, back in for the remainder of the trip . My question is, does my 90 day clock "reset" being that I will be outside of the zone for 90 days? (Even if I only used 60 out of 90 days allowed) Or will it be considered day 61 when I return?
When you first enter Schengen, two clocks will start, one counting 90 days and the other counting 180 days. If you spend all of your 90 days in Schengen or only 60, that doesn't matter - a new 90 days period will only start after the 180 days clock has stopped counting. So if you go back to Schengen after 90 days outside, you'll still be within the first 180 days and you will enter on day 61.
The above might be intended correctly, but at least to me reads wrong. There is no 180 day counter that resets. Any 180 day period has the restriction of only allowing you in the Schengen zone for 90 days. Think of the least convenient way of counting a 180 day period for your trip. That one applies. It's a sliding window.
So, 60 days in Schengen, 90 days outside. Then back to Schengen. That'll be day 61. But by the time day 91 in Schengen arrives, the very first day of the first 60 days will be outside the 180 day window, so you'll have one more day to spend in Schengen, and so on.
Do note that days in Schengen are counted inclusively - so a travel day (arriving or departing) is a full day in Schengen. So those 90 days outside must be a full 90 days outside, with the two travel days not being counted as part of them. With that taken into consideration, your return to Schengen will allow you to stay for 90 days (not 30, not 120).
Thank you both for your help! I've tweaked my itinerary so that I'll be in Schengen for 90 days then out for a full 90 days before I return. I don't want to encounter any problems leaving, especially since I'll be exiting from one of the notoriously strict Scandinavian countries.