See your real tax savings from the mortgage interest deduction — not the headline number, the actual benefit.
Itemizing only helps if your itemized deductions exceed the standard deduction. This calculator does that math properly — using 2026 standard deductions, the $10k SALT cap, and your marginal tax rate.
Direct answers to the most common questions, in plain language. Skim if you're in a hurry; dig deeper below.
Roughly your marginal tax rate × interest paid — but only if you itemize.
If you pay $15,000 of mortgage interest and your marginal federal rate is 24%, the maximum benefit is $3,600. But it only matters if your total itemized deductions exceed the standard deduction ($15,000 single / $30,000 married in 2026).
Only if itemized total exceeds the standard deduction.
Add mortgage interest, SALT (capped at $10,000), charitable gifts, and other itemized deductions. If the total beats the standard deduction, itemize. For most homeowners after 2017's tax reform, the standard deduction wins.
Yes — interest on up to $750,000 of acquisition debt (post-2017).
You can deduct interest on up to $750,000 of mortgage principal ($375,000 if married filing separately) used to buy, build, or substantially improve your primary or secondary home. Older mortgages may qualify under the $1M pre-2018 cap.
Only if the funds bought or improved the home.
HELOCs and home equity loans used for home improvements still qualify under the $750k cap. Funds used for other purposes (debt consolidation, college, vacations) are NOT deductible since the 2017 tax law.
The mechanics in short answers — no jargon, no upsell.
On Schedule A, mortgage interest is one of the major itemized deductions. But you must itemize — meaning your total itemized deductions exceed the standard deduction — to claim it.
If your itemized total is $32,000 and the standard deduction is $30,000, your real benefit is only the $2,000 excess × your marginal tax rate.
Interest is deductible on up to $750,000 of mortgage debt for homes bought after Dec 15, 2017. Older mortgages can use the $1,000,000 cap.
Early in the mortgage, most of your payment is interest — peak deduction. Later, more goes to principal and the deduction naturally drops.
Designed so anyone can model their situation in under a minute, with or without a finance background.
Not the headline number — the actual benefit after the standard deduction floor.
See whether itemizing actually beats the standard deduction for your numbers.
Single, MFJ, head of household — see how marginal rate changes the benefit.
Properly model the $10,000 state-and-local-tax limit that breaks many itemizers.
See how the deduction shrinks as principal is paid down, year by year.
Uses 2026 brackets and standard deduction amounts.
Everything you might ask before, during, or after using this tool.
For 2026, federal brackets are roughly: 10%, 12%, 22%, 24%, 32%, 35%, 37%. Your marginal rate is the bracket your last dollar of income falls into. Use a tax bracket calculator or your last 1040 to find it.
Approximately $15,000 for single, $30,000 for married filing jointly, $22,500 for head of household. The TCJA-era doubled standard deduction is set to revert in 2026 unless Congress acts — these numbers may shift.
After the 2017 tax law doubled the standard deduction and capped SALT at $10,000, only ~10% of households now itemize. To benefit, you typically need a large mortgage balance, high SALT taxes, or significant charitable giving.
A simple rate-and-term refinance keeps your deduction eligibility intact. A cash-out refi only keeps the deduction on the original acquisition debt portion — funds taken out for non-home purposes are NOT deductible.
Points paid to buy down your rate are typically deductible — fully in the year paid for a home purchase, or amortized over the loan life for a refinance. Add these to your interest figure.
Yes — but they're combined with state and local income/sales taxes under the $10,000 SALT cap. Most homeowners hit this cap quickly, which is why itemizing has become less attractive.
Mortgage interest on acquisition debt is allowed for AMT, but home equity interest (even for improvements) was disallowed for AMT historically. For most taxpayers in 2026, AMT no longer applies due to higher exemptions.
Yes, but the cap drops to $375,000 of mortgage principal, and both spouses must either itemize or both take the standard. Most MFS couples find this worse than filing jointly.
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The deduction is an itemized deduction on Schedule A — it only matters if your total itemized deductions exceed the standard deduction.
For 2026, that floor is ~$15k (single) / ~$30k (MFJ). Below that, the deduction is mathematically worthless to you.
When it does matter, the value is roughly: (itemized total − standard deduction) × your marginal tax rate. The headline "I paid $15k in mortgage interest, that saves me $3,600!" is almost always wrong.
The 2017 Tax Cuts and Jobs Act roughly doubled the standard deduction AND capped state-and-local-tax deductions at $10,000.
Result: even a $400k mortgage at 7% (about $28k of interest year-1) plus the SALT cap rarely beats the $30k MFJ standard deduction.
Itemizers dropped from ~30% of households to ~10% almost overnight.
Some TCJA provisions are scheduled to sunset after 2025, which could change the math — this calculator uses 2026 numbers.
Large mortgages in high-cost areas (e.g., $750k+ at 7%+ → $50k+ interest).
Significant SALT (high state income tax + property tax close to or above the $10k cap).
Big charitable giving on top of housing.
Self-employed or with major unreimbursed medical events.
Outside these scenarios, the standard deduction usually wins.
Don't prepay your mortgage just to "save the deduction" — you save much more by reducing the loan than you ever could on tax savings.
Bunching deductions (concentrating charitable giving every other year) can push some borderline taxpayers above the standard deduction in alternating years.
A donor-advised fund lets you front-load several years of giving into one year to clear the standard deduction floor.
Two short notes worth reading before you trust any number on this page.
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Results are not financial, legal, or tax advice. Please consult a qualified professional before any decision about your loan, investments, or personal finances. Actual loan terms and charges depend on your bank and individual circumstances.
