Capital Gain on Home Sale

I received ownership of my mothers home through a Dollar-Deed transfer six years ago.
I will be selling the home this year and don't know how much of capital gain to recognize and what is my basis to use.

The cost basis is your mother's original basis. The famous "dollar deed" tactic means your mom gifted you the home. No sale occurred.

In real estate there is no step-up in basis for a gift. The basis is what your mother paid for the home originally (or inherited), plus the cost of improvements.

If you have been using it as your primary residence in 2 of the past 5 years, you can exclude $250,000 of capital gains, up to $500,000 if you are married.