Multifamily duplex question

[Harold Groetsema]

How does Capital gains work if I purchase a duplex, live in one side as my primary residence and rent out other side. After 2 or three years I decide to sell duplex for say $60K more than I bought it for. Would I only be able to take half of the gains tax free or be able to take the full amount? I can't find a search button because I'm sure this has been discussed.

Thank you