1 or 2 days in Tallinn?

Are you coming from Helsinki? If you are, then I would try to stay two nights to make it worth while. If you were to leave bright and early you could be there early and have most of one day and some of the next. You definitely don't need to spend longer than 2 days in Tallinn though.

We are traveling from Stockholm to Tallinn. Is 2 days too much?

2 days would be good--you can easily spend an entire day wandering the twisty little cobblestone streets of Old Town, lots to see there in a contained area, and for a second day there are various museums, including an outdoor living history one and the zoo, also a water park. If seeing a bit of the surrounding countryside appeals then I highly recommend taking a day tour with EstAdventures--they're limited to 7 people in a passenger van and you'll really get a feel for Estonia as a whole.

Here's a link for a fun tour we took several years ago when visiting Tallinn. They had just started their venture (Brew with a View) and I see it has apparently either morphed into or become a part of Est Adventures. Anyway, it was a lot of fun and the "brews" were good, too! http://www.estadventures.ee/view-with-a-brew-tallinn-walking-tour.html We loved Tallinn and hope to return some day soon.

We will have our 2 teenagers with us…is Brew with a View appropriate? I looked up the site, it looks like a great tour.

Karin, I think the tour would be appropriate as I'm sure they would be offered something other than the local brews. You might send the company an email asking what options might be available for your teens. The walking part was a lot of fun and very informative. The stops along the way in the pubs were each an opportunity to talk with the guides informally about their city. Although it was a while ago, I still count that walking tour among my favorite travel memories.