Making one extra mortgage payment each year is one of the simplest and most powerful ways to pay off your home faster. On a typical 30-year mortgage, this single hack can cut 4 to 6 years off your loan and save you $40,000 to $80,000 in interest, depending on your rate and balance. It works because every dollar above your scheduled payment goes directly to principal, which shrinks the balance that future interest is calculated on.
Unlike refinancing, this strategy costs nothing to set up, requires no application, and doesn't reset your loan term. You stay in control and can stop anytime. Below, we'll break down the math, show real savings numbers, walk you through how to do it, and help you decide if it's the right move for your finances.
What Is the One-Extra-Payment-a-Year Hack and How Does It Work?
The one-extra-payment-a-year hack is a prepayment strategy where you make 13 mortgage payments in a calendar year instead of 12. That extra payment is applied entirely to your loan's principal balance, bypassing the interest portion of a normal payment. Because mortgages are front-loaded with interest, reducing principal early has an outsized effect on what you owe over the life of the loan.
Here's the math in plain English: your monthly mortgage payment is split between interest (calculated on the remaining balance) and principal (which actually reduces the loan). At the start of a 30-year mortgage, roughly 75-80% of each payment goes to interest. When you send an extra principal-only payment, you're not paying any interest on that money — 100% of it reduces your balance. Every future month's interest is then calculated on a smaller number, which means more of your regular payment also starts going to principal. It compounds in your favor.
Let's use a concrete example. Imagine a $320,000 mortgage at 6.5% interest on a 30-year fixed loan. Your principal-and-interest payment would be approximately $2,022 per month. Over 30 years, you'd pay about $408,000 in interest alone — more than the original loan itself.
Now add just one extra payment of $2,022 each year (you could pay it as a lump sum, or split it into $169 added to each monthly payment). That single change knocks roughly 5 years off your loan and saves you about $69,000 in interest. You didn't refinance, didn't change your rate, and didn't dramatically alter your budget — you just redirected one paycheck a year to principal.
How Much Can You Actually Save?
The savings depend on three factors: your interest rate, your remaining loan term, and how much extra you pay. The earlier in the loan you start, the bigger the impact. Here's a side-by-side comparison using our $320,000 at 6.5%, 30-year baseline:
| Scenario | Monthly Payment | Total Interest | Payoff Date | You Save |
|---|---|---|---|---|
| Standard 30-year loan | $2,022 | $408,142 | Year 30 | — |
| +$100 extra per month ($1,200/yr) | $2,122 | $364,790 | Year 26.5 | $43,352 + 3.5 years |
| +$250 extra per month ($3,000/yr) | $2,272 | $313,180 | Year 22.5 | $94,962 + 7.5 years |
| +$500 extra per month ($6,000/yr) | $2,522 | $248,820 | Year 18 | $159,322 + 12 years |
The one-extra-payment hack (paying $2,022 once a year, or roughly $169/month) falls between the $100 and $250 rows — saving around $69,000 and cutting about 5 years. You can model your exact numbers using our extra payment calculator to see how different amounts affect your personal loan.
Notice how the savings scale faster than the extra payment amount? That's compounding interest working backwards in your favor. Doubling your extra payment from $100 to $250 doesn't just double your savings — it more than doubles them, because you're cutting more of the high-interest early years off the loan.
Step-by-Step: How to Make One Extra Payment a Year
- Confirm your loan allows prepayment without penalty. Most modern US mortgages do, but check your loan documents or call your servicer. Look specifically for a "prepayment penalty" clause — if you have one, calculate whether the penalty is less than your projected interest savings.
- Choose your payment method. You have three options: pay one full extra payment as a lump sum (often using a tax refund or bonus), divide it by 12 and add roughly 1/12 to each monthly payment, or switch to biweekly payments which naturally creates one extra payment per year. Our biweekly payment calculator shows how that option compares.
- Tell your servicer to apply the extra to principal. This is critical. Without instructions, many servicers apply extra money to future payments or escrow — which doesn't save you any interest. Write "apply to principal only" in the memo of a check, or use the "additional principal" field in your online portal.
- Verify the payment was applied correctly. Check your next statement to confirm your principal balance dropped by the full extra amount. If it didn't, call your servicer immediately. Pull your amortization schedule and compare it to your statement.
- Automate it if possible. Set up an automatic recurring extra principal payment through your bank or servicer's website. Automation removes willpower from the equation and ensures consistency, which is where the real long-term savings come from.
- Re-run the numbers annually. Each year, check your remaining balance and recalculate your savings. If your income grows, consider bumping up the extra amount. Even an extra $50 per month on top of your annual payment can knock another year off.
- Keep your emergency fund intact first. Before sending extra money to the mortgage, make sure you have 3-6 months of expenses in cash. A paid-down mortgage doesn't help if you lose your job and can't access the equity quickly.
Common Mistakes Homeowners Make with Extra Payments
- Not specifying "principal only." This is the single biggest mistake. If you just send extra money without instructions, many servicers will credit it toward your next month's payment, putting you "ahead" but not reducing principal. You'll save zero interest. Always include written instructions.
- Paying extra while carrying high-interest debt. If you have credit card debt at 22% APR, paying down a 6.5% mortgage is mathematically backward. Tackle the higher-rate debt first, then redirect those payments to the mortgage. Explore alternative payoff strategies that prioritize your highest-cost debt.
- Skipping retirement contributions to pay extra. If your employer offers a 401(k) match, taking it is an instant 50-100% return. No mortgage prepayment can beat that. Max your match first, then consider extra mortgage payments.
- Forgetting about the mortgage interest deduction. If you itemize taxes, mortgage interest is deductible. Paying down faster reduces this deduction. For most homeowners post-2017, the standard deduction is larger anyway, but high earners in high-cost states should run the numbers with a tax professional.
Is the One-Extra-Payment Hack Right for You? Key Questions to Ask
- Do I have 3-6 months of emergency savings? If no, build that first. Liquidity matters more than a smaller mortgage balance during a job loss or medical emergency. Money sent to your mortgage isn't easily retrievable.
- Am I getting my full employer 401(k) match? If no, contribute enough to get the match before sending extra to your mortgage. A 100% match is a guaranteed return no prepayment can match.
- Is my mortgage rate higher than what I could earn investing? Historically, long-term stock market returns average 7-10%. If your rate is 4%, investing may win. If your rate is 7%+, prepaying is often the better risk-adjusted choice. Consider your personal risk tolerance.
- Do I plan to stay in this home for at least 5 more years? If you might sell soon, the interest savings from extra payments are smaller and you'd be locking up cash unnecessarily. Renters-by-2027 should think twice.
Frequently Asked Questions
Does one extra mortgage payment a year really make a difference?
Yes — a significant one. On a $320,000 loan at 6.5%, one extra payment per year saves approximately $69,000 in interest and pays the loan off about 5 years early. The exact savings depend on your rate and how early in the loan you start, but the impact is always meaningful.
When is the best time of year to make the extra payment?
Earlier in the year is mathematically better because the principal reduction compounds longer. Many homeowners time it with their tax refund in February or March. However, any consistent timing works — what matters most is that you actually do it each year.
Is it better to make one lump-sum extra payment or spread it across 12 months?
Spreading it (adding 1/12 of a payment each month) saves slightly more interest because the principal reductions happen sooner. The difference is small — typically a few hundred dollars over the life of the loan. Choose whichever method you're more likely to stick with consistently.
Will my monthly payment go down after I make an extra principal payment?
No. Your required monthly payment stays the same — only the loan term shortens. If you want a lower monthly payment, you'd need to ask for a "recast," which some lenders offer for a small fee (typically $250-$500) after a large principal reduction.
Should I make extra payments or refinance to a 15-year mortgage?
If current rates are at least 0.75% lower than your existing rate, refinancing to a 15-year may save more. But refinancing has closing costs ($3,000-$6,000) and locks you into a higher required payment. Extra payments are free, flexible, and you can stop anytime. For most homeowners with rates above 6%, the flexibility of extra payments wins.
The bottom line: making one extra mortgage payment per year is one of the highest-return, lowest-effort financial moves available to American homeowners. It requires no application, no fees, and no permanent commitment — yet it can save you tens of thousands of dollars and put you years closer to owning your home outright. Run your own numbers with our free extra payment calculator to see exactly how much you'd save based on your loan balance, rate, and term.