Capital Gains Q

We need to sell our home less than 2 years of living in it. Generally, for capital gains, what is looked at? It will sell for about $40k more than what we purchased it for 1.5 years ago, but we will lose a little based on how much of a downpayment we put down. Does it just take into account that the selling price was more? So taxed on 40k or also our equity aka we have no gains…

Yes, sucks. But we need to move home to take care of a parent, so I don’t want comments about how stupid this purchase was.