Finance category
Mortgage, loan, investing, tax, and money calculators.
Mortgage Interest Deduction Calculator
The mortgage interest deduction only helps if your total itemized deductions beat the standard deduction. This calculator applies the $750k acquisition debt cap and compares itemizing to the 2026 standard deduction so you can size the real tax benefit.
from form 1098
SALT, charitable, medical
Tax savings from MID
$0
benefit beyond standard deduction
Deductible mortgage interest
$18,500
capped at $750k loan limit
Total itemized
$27,000
Standard deduction
$31,500
take standard
How the MID works
Your total itemized deductions are less than the standard deduction. Take the standard — the MID provides no current tax benefit.
Loans originated after 12/15/2017 are limited to mortgage interest on the first $750k of acquisition debt ($375k MFS). Pre-12/15/2017 loans grandfathered at $1M. SALT cap of $40k household ($20k MFS) for joint filers under $500k AGI also affects the itemize-vs-standard math.
EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.
Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.
Learn more about our review process on the EveryCalc methodology page.
How this calculator works
What this page estimates
This Mortgage Interest Deduction Calculator is built to give a quick, browser-based estimate for mortgage interest deduction. The mortgage interest deduction only helps if your total itemized deductions beat the standard deduction. This calculator applies the $750k acquisition debt cap and compares itemizing to the 2026 standard deduction so you can size the real tax benefit. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.
Calculation approach
The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.
Example workflow
For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.
Practical checks
- Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
- Run a low, base, and high case when the inputs are estimates.
- Check the related calculators below when the next decision depends on a different assumption.
How to interpret the mortgage interest deduction result
Best use
Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.
Cross-check
Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.
Watch for
Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.
This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.
Before relying on this mortgage interest deduction estimate
Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.
Confirm source numbers
Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.
Separate cash flow from total cost
A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.
Run conservative cases
Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.
Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.
How to Use
- Enter the annual mortgage interest from your Form 1098.
- Enter your average loan balance — if it exceeds the acquisition cap, the deductible portion is prorated.
- Pick the loan origination period: after 2017 ($750k cap) or before 12/15/2017 ($1M cap grandfathered).
- Enter other itemized deductions (SALT up to $40k joint, charitable, medical over 7.5% AGI).
- Pick filing status and marginal tax rate to see whether itemizing beats the standard deduction and by how much.
Frequently Asked Questions
How does the $750,000 cap work?
For acquisition debt on a primary or second home originated after 12/15/2017, only interest attributable to the first $750,000 of principal ($375k MFS) is deductible. If your loan balance is $900k, you deduct 750/900 ≈ 83.3% of the interest paid.
Does home equity debt still qualify?
Under current law, home equity interest is only deductible when the loan proceeds are used to buy, build, or substantially improve the home that secures it. Debt used for personal purposes (car, credit cards, tuition) is not deductible.
What if I'm close to the standard deduction?
Bunching strategies help — pay two years of property tax in one calendar year, or group multi-year charitable giving via a donor-advised fund — to itemize every other year while taking the standard deduction in alternating years.
Does refinancing reset the cap?
Refinancing a pre-12/15/2017 $1M loan keeps the grandfathered $1M cap up to the remaining balance. Cash-out refinancing that increases principal beyond the original balance makes the new portion subject to the $750k rules.
Related Calculators
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Cash-Out Refinance Calculator
Check how cash-out impacts the deductibility of new principal.
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