The Mortgage Interest Deduction: What It Actually Saves You
Homeowners can deduct interest paid on up to $750,000 of mortgage acquisition debt (or $1,000,000 for loans from before December 16, 2017), but only if they itemize deductions instead of taking the standard deduction. This is the key catch most people miss: the deduction only creates real savings for the portion of your itemized total that exceeds the standard deduction ($15,000 single, $22,500 head of household, or $30,000 married filing jointly for 2025). If your mortgage interest plus other itemized deductions (like the $10,000 SALT cap and charitable gifts) still falls short of the standard deduction, the interest you paid provides zero additional tax benefit — you're already getting a bigger deduction automatically. Your real savings equal your marginal tax rate applied only to the amount by which itemizing beats the standard deduction, not your full interest payment.
2025 Standard Deduction by Filing Status
| Filing Status | Standard Deduction |
|---|---|
| Single | $15,000 |
| Head of Household | $22,500 |
| Married Filing Jointly | $30,000 |
Because the Tax Cuts and Jobs Act nearly doubled the standard deduction, far fewer homeowners itemize today than before 2018 — many discover their mortgage interest isn't actually saving them anything once other deductions are added up.
Frequently Asked Questions
Yes — $750,000 of acquisition debt for loans after Dec 15, 2017, or $1,000,000 for older loans.
No — it only helps once your itemized total exceeds your standard deduction.
Your marginal tax rate times the portion of deductible interest that pushes your itemized total above the standard deduction.
※ Estimate only. Consult a tax professional for your exact itemized deduction calculation and current-year IRS figures.