What determines the taxation of capital gains?

[Robyn Smyles]

My husband and I are new to this community but we have been buying, renovating, and selling homes for 28 years.  We buy, live in it and then sell.
We literally do it all! The find, the design, the demo ( I love demo), the building, and sourcing of materials at deep discount ( love this more). 

We are in the final days of a whole home remodel.  The market is great and we are considering selling! But we always have held it for atleast 2 years to avoid capital gains. 
we average 125-250k profit on each flip.

We are contemplating selling but need to know what income is used to calculate the capital gains tax on the profit ( less the deductibles ) 

Since my husband is a w-2 and I a 1099, is it calculated on the combined income before my write offs or is it on the adjusted gross income ? 

April will be 2 years so it might make sense to wait? 

Would love to get clarity on this!