Just in case - assuming TT remains as it is and the Tax and Interest worksheet require a manual entry for deductible interest. Here's the formula for multiple 1098s on the same loan/house. For this example I'll assume 3 1098s for the same home in 2020 (this will work for as many 1098s as you might have for the same home). No cash out. The idea is to calculate the average loan balance. I suggest 'weighting' the balances for the months the loan balance was carried. The Loan Value (LV) is the mortgage balance in each Box 2 of the 1098. The months held (M) is the number of months held in 2020 for each of the loans.
Average Balance = [LV1 * (M1/12)] + [LV2 * (M2/12)] + [LV3 * (M3/12)]
For instance, you have 3 1098s; $1,230,000 for 2 months; $1,225,000 for 3 months, and $800,000 (you won lottery and applied to loan 🙂 ) for 7 months.
Average Balance = [1,230,000 * 2/12] + [ 1,225,000 * 3/12] + [ 800,000 * 7/12] = $977,917
To establish your limit, divide $750,000 (assumes all loans are post 2017) by the Average Balance you just calculated. For the example here, the Limit Ratio = 750,000/977,917 = 76.7%
Now multiply this ratio by the TOTAL mortgage interest from the three 1098s and you get your deductible Mortgage Interest.
Boom!
Keep in mind that if you have a second home you're also considering, simply add that average balance and calculate the Limit Ratio, and then apply that against the TOTAL Mortgage interests from the two homes on all the 1098s.
Theres another thread on this @Monsterdaddy
