How do I calculate my mortgage interest deduction if I have two mortgages (on my principal residence) that exceed $750k when combined, with different rates on each mortgage? for example one mortgage with $800k at 5% and another mortgage with $100k at 6%? Do I deduct the interest on the mortgage with the higher rate first ($100k at 6%), then the remaining balance of $650k at 5%? Or do I have to calculate a weighted average?
