"You get a tax break for owning a home" is another one of those phrases that's true but incomplete, the size of the break depends heavily on your numbers, and for a lot of owners it's smaller than the folklore suggests. The Buy vs Rent calculator now factors this in directly, instead of ignoring it. Here's the mechanic behind the number it shows you.
The mechanism
Mortgage interest and property tax are both itemizable deductions on a federal return. But itemizing only helps if your total itemized deductions exceed the standard deduction, for 2025, that's $15,000 for a single filer and $30,000 for a married couple filing jointly. If your itemized total doesn't clear that bar, you take the standard deduction instead, exactly as you would if you rented, and owning the home hasn't reduced your taxes at all.
There's a second constraint that matters even more for a lot of owners: state and local tax (SALT) deductions, property tax plus state income tax, combined, are capped at $10,000 under current law. That cap, from the 2017 Tax Cuts and Jobs Act, means that in states with meaningful property tax or state income tax, a big chunk of what you might expect to deduct is simply not deductible past that ceiling. It's the single biggest reason the real-world tax benefit of owning tends to be smaller than a back-of-envelope "mortgage interest is deductible" calculation implies.
Put together, the tax savings from owning isn't your full mortgage interest, and it isn't your full property tax bill. It's the marginal tax you avoid on the portion of your itemized deductions that exceeds the standard deduction, after the SALT cap has already trimmed what counts.
A worked example
Take a household earning $150,000, buying a $600,000 home with a $480,000 mortgage at 6.5%, in a state with a roughly 5% income tax rate. These numbers are illustrative, not a real return, but they're realistic enough to show the shape of the math.
- Mortgage interest, year one: roughly $31,000 (a 30-year loan at 6.5% is interest-heavy in the early years).
- Property tax: say 1.1% of home value, or about $6,600 a year.
- State income tax: roughly $7,500 at a 5% rate on $150,000.
- SALT deduction, capped: property tax ($6,600) plus state income tax ($7,500) totals $14,100, that exceeds the $10,000 cap, so only $10,000 of it is deductible, not the full $14,100.
- Total itemized deductions: $31,000 in mortgage interest plus the $10,000 capped SALT deduction = $41,000.
- Standard deduction (married, 2025): $30,000.
- Amount itemizing actually saves you: $41,000 − $30,000 = $11,000 of additional deductions, over what you'd get anyway by taking the standard deduction.
- Tax savings at a 22% marginal federal rate: with roughly $41,000 in deductions against $150,000 of income, taxable income lands around $109,000, squarely in the 22% bracket for a married couple in 2025, not the top of their income. $11,000 × 22% ≈ $2,420 for the year.
That $2,420 (not $31,000, not $41,000) is the real number: what itemizing actually saved this household over just taking the standard deduction. It shrinks in later mortgage years as the interest portion of the payment declines, and it shrinks or disappears entirely for owners whose itemized total doesn't clear the standard deduction to begin with.
What this simplifies away
This is a simplification, and it's worth being explicit about what it leaves out: mortgage insurance premiums, points paid at closing, itemized-deduction phase-outs at high income, the Alternative Minimum Tax, and the fact that state tax returns often have their own itemization rules that diverge from the federal ones. The $10,000 SALT cap is current law, not a permanent feature of the tax code, it's scheduled to change and could be adjusted, repealed, or extended by future legislation, and this tool uses today's figures, not a forecast of what they'll be when you actually own the home.
None of this is tax advice. Nestward is a planning and educational tool, not financial, investment, tax, legal, or accounting advice. Consult a qualified, licensed tax professional for your actual situation before making a decision based on the numbers here. As with every other calculation on this site, all of this runs in your browser, no figures you enter are transmitted or stored.
Try it with your own numbers
The Buy vs Rent calculator now includes this tax benefit in its estimate of the cost of owning, using your income, home price, mortgage rate, and property tax rate. Change the inputs and watch how much the SALT cap and the standard deduction comparison move the result, it's usually a smaller effect than people expect, and sometimes it's close to zero.