1) was the property ever rented out or did you ever take a home office deduction?
2) did you use it as your personal residence any 2 out of 5 years (or less) ending prior to the date of sale?
3) did you own it any 2 years out of 5 years (or less) ending prior to the date of sale?
the 2 years do not have to be consecutive
if the answer to 1 is no and 2 and 3 are yes, then the gain is fully excludable and does not need to be reported
if the answer all 3 is yes then any gain up to the depreciation taken is recaptured (as 1250 gain) and you need to report it
if the answer to 2 or 3 is no the entire gain will be taxable any depreciation taken would need to be recaptured