Your mortgage interest might not lower your taxes if your total itemized deductions (mortgage interest + other deductible expenses) aren't higher than the standard deduction, the loan doesn't meet IRS rules (e.g., used for non-home improvements), or you're subject to the Alternative Minimum Tax (AMT), but the most common reason is just that the standard deduction offers a bigger tax break.
If the loan is not secured by a home that you own, the interest is not deductible. A mortgage loan is normally secured by the home that the loan was used to purchase. Answering this question incorrectly is probably the most common reason that mortgage interest is omitted from Schedule A.
Homeowners may refinance mortgage debts existing on 12/15/2017 up to $1 million and still deduct the interest, so long as the new loan does not exceed the amount of the mortgage being refinanced. The Act repealed the deduction for interest paid on home equity debt through 12/31/2025.
In most cases, you can deduct all of your home mortgage interest. How much you can deduct depends on the date of the mortgage, the amount of the mortgage, and how you use the mortgage proceeds.
The Canada Revenue Agency isn't so generous, and as such, mortgage interest on a principal residence is generally not deductible as the Income Tax Act considers interest to be a capital expense.
A recent tax law, the "One Big Beautiful Bill Act" (OBBBA) from mid-2025, solidified the mortgage interest deduction (MID) by making the $750,000 debt limit permanent and added new provisions, like treating Private Mortgage Insurance (PMI) as deductible interest for some, starting in 2026, though income phase-outs apply for the PMI deduction. This bill provides clarity by confirming the $750,000 cap for most new loans and reinstating PMI deductibility for lower-to-moderate-income borrowers, easing some homeowner tax burdens.
The mortgage interest deduction (MID) is worth it only if your total itemized deductions (including mortgage interest, property taxes, and charitable giving) exceed the much higher standard deduction, which is rare for many due to tax law changes. It reduces taxable income, saving money for those who itemize, especially those with large mortgages and high interest rates early in their loan, but it requires extra paperwork (Form 1098) and effort.
Mortgage interest deduction is permanent
Trump's 2025 tax cuts and spending legislation makes the mortgage interest deduction cap permanent. This deduction was set up to expire after 2025 under the TCJA, and revert to the previous $1 million cap.
If the loan is not a secured debt on your home, it is considered a personal loan, and the interest you pay usually isn't deductible. Your home mortgage must be secured by your main home or a second home. You can't deduct interest on a mortgage for a third home, a fourth home, etc.
The biggest tax mistakes people make include filing late, math errors, incorrect personal info (like Social Security numbers), forgetting deductions/credits (like EITC), misreporting income, not signing forms, and making errors with bank details for direct deposit, all leading to delays, penalties, or missed savings, with using tax software or professionals helping avoid these common pitfalls.
“If you invest the money you would've used to pay off your mortgage into a retirement account, your return over the long term may exceed the savings of paying down your mortgage,” Poorman says. You're getting a decent tax deduction. It's deductible and the mortgage interest may make your effective tax rate even lower.
For 2025, you can generally deduct mortgage interest on up to $750,000 of home acquisition debt ($375,000 if married filing separately), but a higher limit of $1 million ($500,000 MFS) applies to mortgages taken out before December 16, 2017, and you must itemize deductions to claim it. Interest on home equity loans is only deductible if the funds were used to buy, build, or substantially improve your home.
The interest you pay on a mortgage on a home other than your main or second home may be deductible if the proceeds of the loan were used for business, investment, or other deductible purposes. Otherwise, it is considered personal interest and isn't deductible.
But the Canada Revenue Agency (CRA) looks at your mortgage as a personal expense that does not normally qualify for credits. However, if you run a business from home or if you are eligible to claim home employment expenses, you might be able to deduct the interest paid on your mortgage.
No, mortgage interest isn't always 100% deductible; it depends on loan specifics, use of funds, and loan date, with current limits capping deductible interest on loans after 2017 to the first $750,000 (or $375,000 if married filing separately) used for buying, building, or improving a home, requiring you to itemize deductions to benefit.
Although finance costs, predominantly loan interest, are now disallowed as an expense that can be utilised to reduce taxable rental income, these charges do qualify for a tax credit limited to 20% basic rate Income Tax.
The mortgage interest deduction limit is generally on the first $750,000 of mortgage debt for loans taken out after December 15, 2017, used to buy, build, or improve a home, with a lower limit of $375,000 for married couples filing separately; however, mortgages from before that date have a higher limit of $1 million ($500,000 MFS). You must itemize deductions, and the deduction applies to primary and second homes, including interest on home acquisition debt and sometimes home equity debt if proceeds are used for home improvements.
Many business expenses are 100% deductible, including advertising, employee wages, rent, supplies, and certain business meals like company parties or meals for the public, while personal deductions like student loan interest or charitable donations (depending on the type) can also be fully deductible for individuals. The key is that the expense must be "ordinary and necessary" for your trade or business or meet specific IRS criteria, often differentiating from the 50% rule for client meals.
It's better to itemize if your total eligible expenses (mortgage interest, state/local taxes up to a limit, charitable donations, medical costs) exceed the Standard Deduction amount for your filing status; otherwise, taking the Standard Deduction is simpler and saves more money. You must choose one method, and the goal is always to reduce your taxable income the most, so compare the totals and pick the larger figure.