step dad passed away in Jan.2013 left house to mom we decided to put it into both our names plus my husband she owns 99% and I own 1% if we sell will either of us have to pay capital gains ? House value are hers 80 thousand and mine 90 thousand

Your math doesn't add up. If your mother's 99% share has a market value of $80K, then your 1% share is worth $808.08. Where do you get $90K from? I assume that the $80K figure is her cost basis, which is set by the fair marlet value of the house as of the date of death of your step dad.

First, please cverify that the house is titled as "tenants in common," and not "joint tennants with rights of survivorship." Under tenancy in common (abbreviated TIC) the percentage that each party owns is specified and each can sell his or her piece independently of the other. Under Joint Tenancy with Rights of Survivorship (JTWROS) each is a 50% owner, and if one owner dies the other takes full title.

Assuming you are Tenants in Common - when the house sells you will each record a capital gain equal to your share of the gain. For example if the house seells for $100K then your mother's portion is 99% of that, or $99K, and her gain is $99K - 80K = $19K. She may qualify for an exclusion in reporting that gain if the house is her main home for at least two of the five years prior to selling. Your share of the sell price is $1000, and you would report a gain of $1000 - $808 = $192.

step dad passed away in Jan.2013 left house to mom we decided to put it into both our names plus my husband ...

I find it hard to believe that the probate rocess has been completed and the property has been distributed in just three months or so. Did your parents own the property as joint tenants with right of suviviorship?