Making one extra mortgage payment per year is one of the simplest and most powerful debt-reduction strategies available to homeowners. On a typical $320,000 mortgage at 6.5%, this single move can save you over $70,000 in interest and pay off your home roughly 5 years early. The hack works because that entire extra payment goes directly toward your principal balance, skipping the interest calculation entirely.
What Is the One Extra Payment a Year Hack and How Does It Work?
The one-extra-payment-a-year hack is a mortgage acceleration strategy where you make 13 monthly payments per year instead of 12. That 13th payment is applied entirely to your principal balance, which permanently reduces the amount of money the bank can charge interest on for every remaining month of your loan.
Here's how the math works in plain English: every monthly mortgage payment is split between interest (calculated on your current balance) and principal (which reduces your debt). When you make an extra payment that's designated as "principal only," none of it goes to interest. That means your balance drops faster, and because interest is calculated on a lower balance for the rest of the loan, you save money every single month going forward.
Let's use a concrete example. You take out a $320,000 mortgage at 6.5% interest for 30 years. Your standard monthly principal and interest payment is approximately $2,022. Over the full 30 years, you'd pay about $408,142 in interest — more than the home itself cost. Now imagine you make one extra $2,022 payment every December. That single annual habit cuts your loan term down to roughly 24 years and 7 months, and your total interest drops to around $336,500. That's a savings of approximately $71,600 just from being slightly disciplined once per year.
The simple formula to remember: Extra Principal Payment = Permanent Balance Reduction = Compounding Interest Savings for Every Remaining Month. The earlier in your loan you start, the bigger the impact, because more months of compounding work in your favor.
How Much Can You Actually Save?
The savings depend on how much extra you can apply each year. Below is a side-by-side comparison for a $320,000 loan at 6.5% over 30 years, showing what happens with no extra payments versus various extra-payment amounts spread across the year (which is functionally equivalent to one lump sum):
| Strategy | Monthly Payment | Total Interest Paid | Payoff Date | You Save |
|---|---|---|---|---|
| Standard 30-year loan | $2,022 | $408,142 | Year 30 | $0 (baseline) |
| +$100/month extra ($1,200/yr) | $2,122 | $348,917 | Year 25, Month 8 | $59,225 |
| +$250/month extra ($3,000/yr) | $2,272 | $281,494 | Year 21, Month 4 | $126,648 |
| +$500/month extra ($6,000/yr) | $2,522 | $215,373 | Year 17, Month 6 | $192,769 |
| One extra payment/year ($2,022/yr) | $2,022 + 1 bonus | $336,500 | Year 24, Month 7 | $71,642 |
As you can see, even the most modest strategy — one annual extra payment of $2,022 — saves more than $71,000. If you want to see your own personalized numbers, run them through our extra payment calculator to get exact figures based on your loan balance and rate.
Step-by-Step: How to Make One Extra Payment a Year
- Pick a funding source. Decide where the extra payment will come from each year. Common sources include your tax refund (the IRS issues an average refund of around $3,000), a year-end work bonus, or a 13th paycheck if you're paid biweekly (which produces two extra paychecks per year).
- Confirm your loan allows principal-only payments without penalty. Most conventional US mortgages do, but you should call your servicer or read your note to verify there's no prepayment penalty. This is rare on modern loans but still worth a five-minute call to be safe.
- Set a fixed annual date. Choose a specific month every year — many homeowners pick December (after holiday shopping) or April (after tax refunds arrive). Calendar reminders prevent the "I'll do it next month" trap that kills most good financial intentions.
- Designate the payment as "principal only" in writing. When you submit the extra payment, you must explicitly mark it as principal-only. Otherwise, many servicers will apply it to next month's payment, which provides almost no benefit. Most online portals have a separate principal-only payment field — use it.
- Verify the payment was applied correctly. Two weeks after submitting, log into your servicer's portal and check your statement. Your principal balance should drop by the full extra amount, and your interest portion of the next regular payment should be slightly lower.
- Track your progress against your original amortization schedule. Pull up your original amortization schedule and compare. Seeing yourself five or six rows ahead of where you "should" be is powerfully motivating and reinforces the habit.
- Increase the amount when life allows. If you get a raise, dedicate a portion of it to making your annual extra payment larger — or transition to a biweekly schedule, which is equivalent to about 13 payments per year automatically.
Common Mistakes Homeowners Make with Extra Payments
- Not labeling the payment "principal only." This is the single most common error. If you just send extra money without specifying its purpose, servicers often credit it as an early next-month payment, which means most of it gets eaten by scheduled interest. The savings simply don't materialize.
- Paying down the mortgage before high-interest debt. If you carry credit card debt at 22% APR, sending an extra payment to your 6.5% mortgage is mathematically backwards. Eliminate high-interest debt first — your effective "return" on doing so is much higher.
- Skipping the emergency fund. Putting every spare dollar into your house makes the equity inaccessible if you lose your job. Always keep 3-6 months of expenses in liquid savings before aggressively prepaying.
- Refinancing without recasting after extra payments. If you've made significant extra payments and then refinance, you reset the clock. Consider a loan recast (which keeps your term but lowers your payment based on the new balance) instead, when available.
Is the One Extra Payment Hack Right for You? Key Questions to Ask
This strategy isn't universal. Before committing, work through these decision criteria:
1. Do you have at least 3 months of emergency savings already in place? If no, build that first. Once that safety net exists, extra mortgage payments become a much safer bet because you won't be forced to take expensive loans during a setback.
2. Is your mortgage rate higher than what you could reasonably earn investing? If your rate is 6.5%+ and you're not maxing out an employer 401(k) match, the extra payment is often the better guaranteed return. If your rate is 3.5% and you have decades until retirement, investing may win mathematically.
3. Do you plan to stay in this home for at least 5-7 more years? Extra payments build equity, but that equity only pays off if you keep the home or sell after the savings have accumulated. If you might move in 2 years, the strategy is less impactful.
4. Will making the extra payment cause financial stress? If it means skipping retirement contributions or living paycheck-to-paycheck, scale it back. The goal is wealth-building, not financial anxiety. Explore other mortgage payoff strategies if a lump sum feels too aggressive.
Frequently Asked Questions
Is one extra payment a year better than biweekly payments?
They're mathematically very similar. Biweekly payments result in 26 half-payments per year, which equals 13 full payments — exactly one extra. The biweekly approach automates the habit, but if you're disciplined, an annual lump sum is just as effective. You can explore the mechanics with our biweekly payment calculator.
When in the year should I make the extra payment for maximum benefit?
Earlier is mathematically better because the principal reduction compounds for more months. Making a January extra payment saves slightly more interest than a December one. However, the difference is minor — typically less than $200 over the life of the loan — so pick whichever month aligns with your income.
Will making extra payments hurt my credit score?
No. Paying down mortgage principal does not negatively affect your credit. In fact, lowering your overall debt balance can modestly improve your debt-to-income ratio, which matters if you're applying for other credit. Your mortgage account stays open and active until fully paid.
What if my budget doesn't allow a full extra payment of $2,000+?
Start smaller. Even $50 extra per month, applied to principal, can shave 2-3 years off a 30-year mortgage and save $25,000+ in interest. There's no minimum required to benefit — every dollar of extra principal saves you future interest.
Should I make an extra payment if I plan to refinance soon?
Generally, no. If you refinance within 6-12 months, the extra payment savings are small and you're better off keeping that cash for closing costs or holding it in a high-yield savings account. Wait until your long-term loan is finalized, then start the strategy.
The one-extra-payment-a-year hack is proof that you don't need to dramatically overhaul your budget to build serious wealth through your home. A single disciplined moment each year — funded by a tax refund, bonus, or savings — can erase 5+ years of debt and save you the equivalent of a luxury car in interest payments. The key is starting now, because every month you delay reduces the compounding benefit.
Ready to see exactly how much you could save on your specific loan? Run your numbers through our free extra payment calculator and discover your personalized payoff date in under 60 seconds.