Widow Selling Duplex

If you live in one side of the duplex, the IRS will treat your sale as two transactions.  On the half of your sale that represents your own home, you can still use the joint-taxpayers full homesellers exclusion. THat means that for half of your profit, up to $500,000, you'll owe no federal capital gains tax.  That full exclusion is available if you sell within two years of the date of your husband's death.  If you sell after that, you can use the single taxpayers exclusion, to cover a gain of up to $250,000.  But the matter is complicated by the possbility of a stepped-up basis.  All you need to know about that is that it would mean less tax due, perhaps almost none.  Consult a laywer or accountant for details.

The other half of your profit will come from the sale of rental property.  Figuring out the long-term capital gains tax on that half is a complicated matter, involving things like stepped-up basis and recaptured depreciation, and you should certainly have professional help at that point.