Our old family house had all 4 sibling names on deed. Parents both deceased. My unmarried brother lived in it alone. Me and 2 sisters married and living in our own homes. Brother recently died. My sisters and I just sold house for $450,000 and will be splitting it 3 ways. House originally bought for $19,000 in 1970 (Hawaii). After realtor's commission, escrow fees, etc. I figure we probably will make about $130,000 each. About how much tax do you think I will have to pay? Will it affect my husband and my income tax tremendously since this was not our main home?

Humm what about brothers estate, depending on how deed was written. His heirs of any may have claim to his part of home, this will depend on location and exact wording on deed.

Taxes are paid on the capital gains, the profit from puchase value to sale minus cost of sale and the such, ( true profit) at this value, have an accountant properly do taxes on this.

You pay capital gains based on the house's market value at the time you all inherited it, not what your parents paid for it in 1970. That amount should have been determined for probate of the estate, when inventory was done.

You need to get TWO historical appraisals done, one to determine the Fair Market Value (FMV) at the time of death for last surviving parent, then again at the time of death for the brother.

Once you have those appraisals, the calculation of the capital gains tax is relatively simple for any competent tax professional.