Mortgage Tax Deduction Calculator
Estimate your tax savings from the mortgage interest deduction. See whether itemizing makes sense and how much your effective mortgage rate decreases.
How to Use This Mortgage Tax Deduction Calculator
Enter your Loan Amount and Interest Rate to calculate your annual mortgage interest. Select your Filing Status and Annual Income to determine your marginal tax bracket. Choose whether you plan to itemize or take the standard deduction.
The calculator shows your potential tax savings — but only if itemizing your deductions results in a larger deduction than the standard deduction. For many taxpayers after the 2017 Tax Cuts and Jobs Act, the higher standard deduction makes itemizing less beneficial.
The Mortgage Interest Deduction Formula
(Capped at $750,000 of mortgage debt for loans after Dec 15, 2017)
Tax Savings = MAX(0, Annual Interest - Standard Deduction) × Marginal Rate
Effective Rate = Stated Rate × (1 - Marginal Tax Rate)
Standard Deductions (2024): Single $14,600 | Married $29,200 | HOH $21,900
The deduction is only valuable if your total itemized deductions (mortgage interest + state taxes + charitable contributions, etc.) exceed the standard deduction. The marginal tax rate determines how much each dollar of deduction saves you — a 22% bracket saves 22 cents per dollar of deductible interest.
Example: High-Income Couple with Large Mortgage
Tom and Lisa — $600,000 Mortgage, Married Filing Jointly
| Loan Amount | $600,000 |
| Interest Rate | 6.75% |
| Annual Interest (Year 1) | ~$40,500 |
| Standard Deduction | $29,200 |
| Marginal Tax Rate | 24% |
| Incremental Deduction | $11,300 ($40,500 - $29,200) |
| Annual Tax Savings | $2,712 ($11,300 × 24%) |
| Monthly Savings | $226/month |
| Effective Rate | ~6.30% (after tax benefit) |
Note: They still benefit from itemizing because their mortgage interest alone ($40,500) exceeds the standard deduction ($29,200). Adding state taxes and charitable contributions would increase the benefit further.