How much mortgage and home equity loan interest can you now deduct? Prior to the Tax Cuts and Jobs Act (TCJA), you could deduct interest on a total of $1 million in mortgage debt on your principal and second homes and interest on up to $100,000 of home equity debt (subject to conditions). Under the TCJA, from 2018 to 2025, the limit on home acquisition debt is $750,000. But for home loans incurred or refinanced before Dec. 15, 2017, the pre-TCJA limits still apply. Interest on home equity loans isn’t deductible for 2018 (but it’s still deductible on 2017 returns).