Do you have a favorite tax calculator you can use for 2016?

Try: irs.gov, Forms & Publications, 1040 Booklet, page 17

under 19 is one age I see there.

If the son or daughter is your biological child, stepchild, foster child, sibling, step-sibling, or a descendant of any of these individuals, you can claim him/her as your dependent, but the child can’t turn 19 at any time during the tax year (age 24 if a full-time student). Under no circumstances can you claim a child that is older than you. The child also has to live with you for more than half of the tax year and you have to provide at least half of the child’s financial support.

Turbo tax is good. Thanks!

CPT Joseph K Murdock - Once our properties started to accumulate, found it easier to go to a tax preparer. After years of going to one for years we went to another. Con - Discovered the old one was doing it wrong.
Pro - New guy got us several thousand $ back.
Con - That's money we should have had in the first place!
That said, depending on your situation and how up you are on the tens of thousands of pages of tax code, if your situation is as complex as mine, I'd recommend a (good) tax preparer.

I should get a nice chunk of change back! :)