What interest is deductible?

For tax year 2018, the limit is $750,000 ($375,000 for married filing separately) of debt secured by your first and second home for binding contracts or loans originated after December 16, 2017. For loans prior to this date, the limit is $1 million.

The new tax law suspends the deduction for home equity interest, unless the loan is used to "buy, build or substantially improve" the home that secures the loan.