I moved my household with my wife and son on July 13th 2018 to a rental. I own my old house, but have not rented it out. I do want to sell it now; how do I do my taxes?

[rjs · Accepted solution]

The house does not change your 2018 tax return in any way. If you sell it or rent it out in 2019, you will report that when you do your 2019 tax return after the end of 2019.

If you made mortgage payments or paid real estate tax on the house in 2018, you can enter those as itemized deductions, the same as if you has continued to live there. But it will not make any difference in your tax unless your total itemized deductions are more than your standard deductions. (I am assuming that you do not have a mortgage on any other property, and that the house is in the United States.)

The rent does not affect your federal tax return. Some states offer a deduction or credit based on rent that you pay. The rent that you paid in 2018 might qualify for such a deduction or credit, depending on the rules in your particular state. The TurboTax interview for your state will ask you about your rent, if appropriate.

[Hal_Al]

The capital gain on the sale of your principal residence is tax free (up to $500,000 Married). But, to be eligible, you must have owned and lived in the home for at least 2 of the 5 years prior to sale.
For most people, this effectively means you must sell the house within 3 years of moving out or you will lose that tax break.