15 Year Mortgage Amortization Schedule Calculator

Higher Payment Now, or Less Interest Over Time?

That's the entire 15-vs-30 decision, stripped down to its essence. Every other consideration — qualification, cash flow, retirement timing, opportunity cost — flows from how you answer it. A 15-year mortgage forces a kind of financial discipline: you commit to a larger payment every single month, and in exchange the lender charges you less for the privilege of borrowing, because you're promising to pay the loan off in half the time. A 30-year mortgage does the opposite: it minimizes your required monthly outlay and maximizes your flexibility, but you pay for that flexibility in interest, month after month, for three full decades.

Neither answer is universally correct, which is exactly why so much generic advice on this topic falls flat. The right term depends on your income stability, your other financial goals, and how you value the psychological certainty of a fixed payoff date against the mathematical case for investing the difference elsewhere. The rest of this page walks through the actual numbers so you can make that call with real figures instead of a slogan.

Why 15-Year Mortgages Carry Lower Interest Rates

The rate gap between 15-year and 30-year mortgages isn't a marketing gimmick or a reward for "better" borrowers — it's priced risk. When a lender commits to a 30-year fixed rate, it's locking in today's rate for three decades of uncertain future inflation, interest-rate movement, and prepayment behavior. A 15-year commitment carries half that exposure window, so the lender can afford to charge less for it. This is the same reason a 5-year auto loan usually beats a 15-year auto loan in rate, or why short-term bonds typically yield less than long-term bonds in a normal rate environment — duration itself carries a price.

You can see this spread in live market data. Freddie Mac's Primary Mortgage Market Survey — the industry's benchmark weekly rate survey — has consistently shown the 15-year fixed average running below the 30-year fixed average, with a recent published spread of roughly two-thirds of a percentage point. For the worked comparison on this page, we use a representative 6.75% 30-year rate against a 6.25% 15-year rate: a half-point spread that's realistic and slightly conservative relative to what current survey data shows, not an arbitrary or cherry-picked gap.

The Full Side-by-Side Comparison: $350,000 at 6.75% vs. 6.25%

Here is the same $350,000 loan amount run through both terms, so you can see exactly where the money goes in each case. These are the identical assumptions used on our 30-year mortgage amortization schedule page, so the two pages agree with each other — see the full 30-year breakdown there for the complete month-by-month schedule on that side of the comparison.

The 15-year loan costs about $730.89 more per month, but saves roughly $277,057.19 in total interest over the life of the loan. That trade-off — higher payment, lower lifetime cost — is the whole calculation. Whether it's worth it depends entirely on whether your budget can comfortably absorb the extra $731 a month without crowding out other financial priorities.

Who a 15-Year Term Actually Fits (and Who It Doesn't)

A 15-year mortgage is a good structural fit for borrowers who check most of these boxes:

• Stable, comfortably sufficient income— the higher payment doesn't just fit today's budget, it fits a budget that can absorb a job change, a slow year, or a medical bill without the mortgage payment becoming a source of stress.
• A retirement deadline you're building toward — buying a home at 45 and wanting it paid off before retiring at 60 is a common, sound reason to choose 15 years over 30.
• Already maxing out tax-advantaged retirement accounts— if 401(k) and IRA contributions are already at their limits, directing extra cash flow toward a guaranteed, tax-free "return" in the form of a 6.25% interest rate saved is a reasonable use of additional dollars.
• Refinancing with substantial built-up equity— homeowners several years into a 30-year loan who've seen their home appreciate often refinance into a 15-year term at a similar or only slightly higher payment than their original loan.

A 15-year term is usually a worse fit when:

• The higher payment would eliminate your financial cushion— if committing to it means no emergency fund contributions or skipped retirement savings, the guaranteed interest savings aren't worth the fragility it creates.
• You expect to move within 5-7 years— most of the 15-year loan's interest-savings advantage compounds in the later years; if you'll sell before then, a 30-year loan with optional extra payments captures most of the benefit with none of the required commitment.
• You're early in your career with rising but not-yet-established income — a 30-year loan today with the option to refinance into a 15-year term (or simply add extra payments) once income grows preserves flexibility you may need now.

Can You Get 15-Year Payoff Speed on a 30-Year Loan? Yes — But Not the 15-Year Rate

A common workaround is to take the 30-year loan for its lower required payment and flexibility, then voluntarily add extra principal payments to accelerate payoff. This works, partially. Using our extra payments calculator logic on the same $350,000, 6.75% 30-year loan: adding an extra $730.89 a month — matching the exact gap to the 15-year payment — pays the loan off in about 191 months (roughly 15.9 years) instead of 360, with total interest of about $220,970.01.

That's close in time to a genuine 15-year term, but it's still about $30,793.61 more in total interest than the true 15-year loan's $190,176.41. The gap exists for one reason only: the extra-payment strategy pays down the balance at the 30-year loan's 6.75% rate, not the 15-year loan's lower 6.25% rate. Extra payments buy you speed and — critically — the freedom to stop or reduce them in a lean month, which a 15-year loan's contractually higher payment doesn't offer. But they don't buy you the rate discount that comes from committing to the shorter term upfront. If your priority is minimizing total interest paid to the cent, and your budget can sustain it, the true 15-year loan wins; if your priority is flexibility with most of the benefit, extra payments on a 30-year loan (or a later refinance — see our refinance amortization calculator if rates move) are the better fit.

Methodology and Sources

Every figure on this page is generated from the standard fixed-rate amortization formula: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the loan principal, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of monthly payments — 180 for a 15-year loan, 360 for a 30-year loan. We then run a full month-by-month simulation from that formula, tracking the interest and principal split for every single payment, rather than approximating from the summary totals. That's the same engine that powers the calculator at the top of this page and the identical $350,000/6.75%/6.25% comparison used on our 30-year mortgage amortization schedule page, so figures agree across both pages. The current market context on 15-year versus 30-year rate spreads referenced above comes from Freddie Mac's Primary Mortgage Market Survey, the industry's most widely cited weekly average-rate benchmark. Enter your own loan amount and rate into the calculator above for figures specific to your situation — published survey averages and lender-quoted rates will differ from the illustrative 6.75%/6.25% figures used throughout this page.