The basis in the home would be the value of the home at the time of death of your mother, plus any improvements you did to the home after the date of inheritance and before the date of the sale plus costs of sale. You would times the basis and sales price by the ownership percentages to figure the gain for each individual. If the estate was not large enough to file an estate tax return, you probably did not have an appraisal of the property done at the time of death. I would have a real estate (or two) professional give you estimates of the property's worth at the time of death if this is the case. please let me know if you have any questions.