Are you looking at a 1031 exchange?
Are you thinking of capital gains tax?
Rules have changed....so whatever you knew many years ago is likely different today.
Regardless of your situation.....your CPA or tax advisor is in the best position to advise you on such matters.
I think you may be referring to capital gains tax. That is going to depend on if you were owner occupied and how long you lived in it and when, or if it was rental. Plus what gains, if any you had.