I see a lot of questions about personal residence disposals and their tax treatment so I figured I would just post a quick summary.
I once read that there is no other asset class given greater preference by tax law than real estate.
Here is an example under 121.
If you sell a personal residence and meet the ownership and use tests, you can exclude up to 250,000, or 500,000 if married filing jointly. You must meet these tests within 5 years ending on the date of sale, not necessarily consecutively.
After two years, assuming all conditions are met, you can do it again.
Now it can of course get more complicated, for example with a divorce, or with the depreciation of the portion of the home office, but that's the general idea.
Honestly if I don't get a 1099-S and the total proceeds is under 500k, I don't even report it.
BUT* Always give your 1099-S to your CPA. He has to tie that amount out to the 8949, and if it is not done so, the IRS will recalculate your taxes and not in your favor. So if you sold a home for 500,000, they will not subtract the basis from purchase, but will add 500k to your taxable income. I've seen it.
The IRS does not calculate in your favor.
Guys these are great tools if you don't like tax law and regs. Check out pubs and instructions.
Here's a good couple of Pubs:
https://www.irs.gov/forms-pubs/about-publication-523
https://www.irs.gov/forms-pubs/about-publication-527