Most people need a mortgage to buy a home because houses cost far more than a typical household can save in cash within any reasonable timeframe. The median existing home sold for about $398,000 in early 2026,1National Association of Realtors. Existing-Home Sales while median household income is roughly $83,730 a year2U.S. Census Bureau. Income in the United States: 2024 and the national personal savings rate sat at just 3.6% of disposable income at the end of 2025.3U.S. Bureau of Economic Analysis. Personal Saving Rate A mortgage bridges that gap. It also lets buyers keep cash available for other needs, use borrowed money to build equity, and in some cases lower their federal tax bill.
The Math That Makes Cash Purchases Impossible
Start with the numbers a would-be buyer actually faces. A median-income household saving at the national rate puts away roughly $3,000 a year. Reaching $400,000 in cash at that pace would take well over a century. Even a disciplined saver setting aside 20% of gross income would need about 25 years, and that assumes nothing else ever draws down the balance: no car replacement, no medical bill, no child, no job gap.
A mortgage collapses that timeline to the present. A buyer puts down a fraction of the price and repays the rest over 15, 20, or 30 years while living in the home.4Consumer Financial Protection Bureau. Mortgages Key Terms Without that mechanism, homeownership for most working households would be a retirement-age achievement at best.
How Small the Down Payment Can Be
Mortgages don’t erase the need for upfront cash. Buyers still need a down payment, closing costs, and some reserves. But the down payment is a small share of the purchase price, and the minimum depends on the loan.
- Conventional loans backed by Fannie Mae or Freddie Mac can go as low as 3% down on a primary residence for qualifying borrowers, which is $12,000 on a $400,000 home.5Fannie Mae. Eligibility Matrix
- FHA loans require 3.5% down for borrowers with credit scores of 580 or higher, or $14,000 on the same home.
- VA loans require no down payment for eligible veterans, active-duty service members, and certain surviving spouses.6U.S. Department of Veterans Affairs. Purchase Loan
- USDA loans require no down payment for homes in eligible rural and suburban areas.
The distance between saving $12,000 and saving $400,000 is the whole reason the mortgage industry exists. A buyer who can put together a few percent of the price gets access to housing that would otherwise be a generation away.
What Borrowing Actually Costs
Mortgages solve the affordability problem, but the price is interest, and over 30 years it adds up. With rates near 6% in early 2026,7Federal Reserve Bank of St. Louis. 30-Year Fixed Rate Mortgage Average in the United States a buyer putting 20% down on a $400,000 home borrows $320,000. Total interest over 30 years approaches $370,000, and the buyer ends up paying around $690,000 for a $400,000 house.
That number surprises most first-time buyers. It’s also why the loan term matters. A 15-year mortgage at a somewhat lower rate cuts total interest roughly in half, though the monthly payment climbs steeply. Most buyers pick the 30-year term anyway because the monthly number fits their budget, accepting the higher lifetime cost as the price of getting into a house at all.
Keeping Cash Available
Even buyers who could pay cash often choose a mortgage, and the reasoning holds up. Pouring every dollar into a house leaves you asset-rich and cash-poor. Real estate is illiquid. You can’t sell a bedroom to cover a medical bill or a lost paycheck. Selling the whole house takes months, and pulling equity out through a home equity loan or cash-out refinance takes weeks and isn’t guaranteed.
Financing most of the purchase keeps cash on hand for emergencies, retirement contributions, and other investments. A diversified portfolio of stocks and bonds has historically returned more than mortgage interest rates, so borrowed money working in real estate while saved money works in financial markets can produce a better net outcome than putting everything into the walls. This is why financial advisors routinely tell clients to keep liquid reserves even when they could pay a house off tomorrow.
Leverage and Equity
Leverage is the less obvious reason mortgages build wealth. Put 5% down on a $400,000 home and you control a $400,000 asset with $20,000 of your own money. If the home appreciates 5% in a year, that’s a $20,000 gain on a $20,000 investment. The same $20,000 in a savings account paying 4% would earn $800.
Leverage runs both directions. A 5% drop wipes out that $20,000 on paper, and borrowers with thin equity can end up owing more than the home is worth. That risk was on full display during the 2008 housing crisis. Over longer holding periods, though, U.S. residential real estate has generally appreciated, and every monthly payment chips away at the loan balance. Equity grows from both ends: rising value and shrinking debt.
The Tax Deduction Isn’t What Most Buyers Think
The tax code encourages mortgage use by allowing an interest deduction. Taxpayers who itemize can deduct interest on up to $750,000 of mortgage debt used to buy, build, or substantially improve a qualified home.8Office of the Law Revision Counsel. 26 USC 163 – Interest At 6% on a $400,000 loan, first-year interest is about $24,000, and deducting that can save several thousand in tax depending on the bracket.
The catch is that the deduction only helps if total itemized deductions exceed the standard deduction. For 2026, the standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly.9Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 A married couple needs more than $32,200 in combined mortgage interest, state and local taxes, charitable gifts, and other deductions before itemizing pays off. Since the Tax Cuts and Jobs Act raised the standard deduction in 2018, roughly 90% of taxpayers take it. For many homeowners, especially those with smaller loans or living in low-tax states, the mortgage interest deduction is a theoretical benefit they never actually claim.
Borrowers with larger loans, higher rates, or heavy state and local tax bills are more likely to clear that threshold. Property taxes and state income taxes can be deducted alongside mortgage interest, though a federal cap limits the combined state and local tax deduction. The tax benefit is real for some households and irrelevant for others, and it shouldn’t be the reason anyone signs a mortgage.
Why Renting Isn’t a Substitute
Some people look at the interest totals and ask whether renting is smarter. Renting avoids debt and maintenance, but every rent check is gone for good. A mortgage payment splits between interest, which is the lender’s revenue, and principal, which is the borrower’s equity. The principal share grows over time as the interest share shrinks. After 30 years, a renter has receipts; the homeowner has a paid-off house.
Renting also leaves you exposed to a landlord’s choices. Rent can rise, the property can sell, a lease can go unrenewed. A fixed-rate mortgage locks in the housing payment for the life of the loan, which is one of the few real inflation hedges available to ordinary households.
Buying isn’t always better than renting. In expensive markets where prices have run far ahead of rents, renting and investing the difference can win. But for most people in most markets over long time horizons, the forced saving built into a mortgage and the equity that comes with it outperform the flexibility of renting.