Kevin - I replied to this same question in your thread yesterday...
That's your previous post that was replied to incase you're not sure how to find it.
I think that you would be taxed on your total profits unless you did a 1031 tax exchange where you could defer taxes, and roll your monies into another property of greater value.
Each event of a sale of a piece of real estate triggers a recognition of gain.
And unfortunately you cannot do a 1031 exchange if your intent is primarily to resell the property. 1031 exchanges are property in which your intent is to...."hold for productive use in business, trade, or for investment." There is no statutory holding period but the self described industry practice of fixing and flipping implies that your intent is to buy fix and sell - or primarily to sell. So change your model a little. Instead of buy fix sell. Buy fix rent for a bit and then sell using a 1031 exchange and defer all tax. Or buy rent for a while, then fix and sell. Change your intent and gain access to a very powerful tax mitigating tool.