If you sell the personal home that you owned and where you lived as your main home for more than 2 years, you can exclude the first $250,000 of capital gains from taxation. If you are married, you can exclude $250,000 of gains per spouse, assuming both spouses meet the 2 year residency rule.
If you sell after owning and living in the home for less than 2 years, you must generally pay capital gains tax on all the gain. However, if you sell due to certain "unforeseen circumstances", you can claim a partial exclusion of the gain. This is described on page 6 of publication 523.
https://www.irs.gov/pub/irs-pdf/p523.pdf
You can also reduce your capital gains by taking note of adjustments to your cost basis (things beside the basic purchase price that count toward your cost of buying the home). This is listed on page 8 of publication 523.
In the event your capital gains are fully taxable, your capital gains rate is 0% as long as your total taxable income (including the gain) is less than $83,550. Since you would be entitled to a standard deduction of $25,900, this really means that your capital gains rate is 0% as long as your gross income is less than $109,450. If your gain pushes you over that limit, then that part of the gain will be taxable at the long term rate of 15%. (For example, if your other income is $65,000 and your gain is $50,000, the first $44,450 of capital gains would be taxed at 0% and the remaining $5,550 would be taxed at 15%.
