To pay off a 15-year mortgage in 10 years, add enough extra money to each month’s principal payment to compress the remaining loan into 120 months. On a $200,000 balance at 6% interest, that means raising your monthly payment from about $1,688 to about $2,220, an increase of roughly $533. The reward for that five-year acceleration is roughly $37,300 in interest you never pay. The rest comes down to running the numbers for your specific loan, making sure your servicer applies the extra to principal, and choosing whether to do it informally or lock in a shorter term through a refinance.
Calculate the Exact Extra Payment
Pull three figures from your most recent mortgage statement: your current principal balance, your fixed interest rate, and the number of months left on your loan. Run those through any online amortization calculator twice. Once with your remaining term. Once with a 120-month term. The difference between the two monthly payments is what you need to add every month to finish in ten years.
Using the $200,000 example at 6%, the standard 15-year payment of about $1,688 produces roughly $103,800 in total interest over the life of the loan. Shortening the payoff to 10 years pushes the payment to about $2,220 and cuts total interest to roughly $66,400. The earlier you start, the more you save, because your balance (and the interest accruing on it) is highest in the early years.
Check Your Loan for a Prepayment Penalty
Before sending any extra money, confirm your loan doesn’t punish you for paying ahead. Most mortgages originated after January 2014 are qualified mortgages under federal rules, and prepayment penalties are generally banned on those loans. For the small number of non-higher-priced qualified mortgages that do allow penalties, the charges can only apply during the first few years and must meet strict limits.
Your Loan Estimate, which your lender was required to give you before closing, states directly whether your loan carries a prepayment penalty, the maximum amount, and when the penalty period ends. If you can’t find it, check the promissory note or call your servicer. Penalties typically apply only when you pay off the entire balance at once through a sale or refinance, not when you make small monthly principal payments, but get that confirmation from your servicer in writing.
Four Ways to Structure the Extra Payments
You don’t have to refinance or change your loan terms. Any of the following works within your existing contract.
Add One-Twelfth of a Payment Each Month
Divide one monthly payment by 12 and add that amount to every check. On a $1,688 payment, that’s an extra $141 a month. Over a year, you’ve made the equivalent of 13 payments instead of 12. It’s the easiest approach to budget for, but on its own it won’t quite cut a full five years off a 15-year loan. Use it as a floor and add more when you can.
Pay Biweekly
Pay half your monthly amount every two weeks. Because there are 52 weeks in a year, you make 26 half-payments, which equals 13 full payments. Not every servicer offers a true biweekly program, and third-party biweekly services often charge $250 to $400 in setup fees plus a per-payment fee that can total more than a thousand dollars over the life of the loan. You get the same result for free by adding one-twelfth to each monthly payment yourself.
Apply Annual Lump Sums
If your income includes bonuses, tax refunds, or other windfalls, applying a single large payment directly to principal once a year achieves the same acceleration. A lump sum immediately reduces the balance that accrues interest for every remaining month.
Automate a Recurring Principal-Only Payment
Most major servicers let you schedule a recurring principal-only payment through their online portal, separate from your regular monthly payment. Automating removes the risk of forgetting, and consistent small principal payments add up quickly.
To hit exactly ten years, you’ll usually need to combine methods or simply pay the precise extra amount your amortization calculator produced. The structures above are frameworks. The math sets the pace.
Make Sure the Money Hits Principal
Sending extra money is pointless if your servicer doesn’t apply it correctly, and this is where most acceleration plans quietly fail. If you type the extra amount into the regular payment field on your servicer’s website, the system may treat it as an early payment for next month rather than a principal reduction. The money sits in a holding account, interest keeps accruing on your full balance, and your payoff date doesn’t move.
When paying online, look for a separate field labeled “Additional Principal” or “Principal Only” and enter the extra amount there. When mailing a check, write your loan number and “Apply to Principal Only” on the memo line, and include any principal-payment coupon from your billing statement. The CFPB notes that borrowers should confirm extra payments are applied to principal rather than interest.
After your first extra payment, check the next statement. The remaining term or payoff date should have shifted earlier. If it hasn’t, call your servicer immediately. A misapplied payment in month one costs you compounding interest every month after.
Recasting and Refinancing as Alternatives
If you’d rather change the loan itself than manage extra payments on your own, two options exist.
A mortgage recast lets you make a large lump-sum principal payment, after which the lender re-amortizes the remaining balance over your existing term at your existing rate. Your monthly payment drops but the rate and term don’t change. Recasting typically costs a few hundred dollars in processing fees, and most lenders require a minimum lump sum of $5,000 to $10,000. FHA, VA, and USDA loans are not eligible; only conventional loans qualify. A recast pairs well with a plan to keep paying extra voluntarily, because it lowers your required payment without forcing a new rate on you.
A refinance replaces your existing loan with a new one, potentially at a different rate. Refinancing into a formal 10-year mortgage locks in the shorter payoff and removes the temptation to skip an extra payment. Expect the same underwriting you went through the first time: tax returns, W-2s, pay stubs, bank statements, a new appraisal, and a debt-to-income ratio (with the new higher payment) generally at or below 43% to qualify as a qualified mortgage. Borrowers with credit scores of 740 or above usually receive the most competitive rates. Closing costs typically run 2% to 5% of the new loan amount, which on a $200,000 refinance is $4,000 to $10,000.
Refinancing makes the most sense when current rates are meaningfully lower than your existing rate. Divide the closing costs by the monthly savings from the lower rate to find your break-even point; if you plan to stay in the home longer than that, the refinance pays for itself. If your current rate is already competitive, extra payments on your existing loan achieve the same 10-year payoff without spending thousands upfront.
Trade-Offs to Weigh Before You Commit
Faster PMI Cancellation
If you’re paying private mortgage insurance, accelerating principal gives you a concrete near-term reward on top of interest savings. Under the Homeowners Protection Act, you can request PMI cancellation once your principal balance reaches 80% of your home’s original value. Your servicer must grant the request if you’re current on payments, submit it in writing, and can show there are no junior liens. If you don’t request cancellation, the servicer must automatically terminate PMI once the balance is scheduled to reach 78% of the original value. Extra principal payments reach those thresholds years faster than the standard schedule.
Smaller Mortgage Interest Deduction
Less interest paid means a smaller mortgage interest deduction if you itemize. Under current law, you can deduct interest on the first $750,000 of mortgage debt ($375,000 if married filing separately); the One Big Beautiful Bill Act, signed in July 2025, permanently extended this cap. If your total itemized deductions don’t exceed the standard deduction, you weren’t benefiting from the mortgage interest deduction anyway. If you do itemize and you’re in the 24% bracket, every $1,000 of interest you no longer pay costs you about $240 in tax savings. In the later years of a 15-year mortgage the interest portion is already shrinking, so the lost deduction is usually smaller than people expect, and the guaranteed savings from eliminating interest almost always outweigh it.
Whether Investing Would Do More
Every dollar of extra principal earns a guaranteed, risk-free return equal to your mortgage rate. At 6.5%, that’s a 6.5% guaranteed return. When mortgage rates were below 4%, the math clearly favored investing, since long-term stock market returns have historically averaged around 8-10% annually. With rates in the 6-7% range, the gap narrows and the certainty of mortgage savings becomes more attractive against uncertain market returns. If your rate is below 5% and you have decades until retirement, investing extra funds in a tax-advantaged retirement account may build more wealth over time. If your rate is 6% or higher, paying down the mortgage is competitive with historical market returns and carries no risk.
Emergency Savings First
Aggressive principal payments tie up cash in an asset you can’t easily access. Before committing hundreds of extra dollars each month, keep at least three to six months of essential expenses in a liquid savings account. A paid-off home doesn’t help if a job loss or major repair forces you onto a credit card at 22% interest. The usual sequence: eliminate high-interest debt, fully fund emergency savings, capture any employer retirement match, then direct extra cash toward the mortgage.