The rule is that you have to have lived in the house 2 out of the last 5 years. Otherwise, any gain above what you paid will be added to your income. Be sure to go back and look at anything you might have done that would have increased the basis in the house, since you bought it. Did you do any construction on the house, improvements?
If you are selling due to the following exceptions, you will be eligible to prorate the gain:
- because the location of your job changed,
- because of health reasons, or
- for some other unforeseen circumstance.
https://www.irs.gov/publications/p523/ar02.html#en_US_2015_publink10009003
