Since your mother put you on the deed before she died, the house is considered to be a gift to you and your sister. You owe no tax on that gift, and unless your mother's estate was pretty big (> $2M) her estate owes nothing either. But since it's a gift, now that you've sold it your cost basis is the same as her cost basis was. That would be her original purchase price plus the cost of any capital improvements or repairs she made. You and your sister together will owe capital gains on the difference between the sales price and your cost basis, less the cost of the sale. So, do you know what your mother's cost basis was?
|