Should You Make Extra Mortgage Payments? Here's the Real Math on One a Year
Does one extra mortgage payment a year actually make a difference? Yes, on a typical 30-year loan, one extra payment a year usually cuts the loan to around 24 to 25 years and saves well over $100,000 in interest and you can spread that extra payment across 12 smaller monthly amounts instead of paying it all at once.
I tell almost every first-time buyer I work with the same thing: if you can manage it, make one extra mortgage payment a year. A $2,500 monthly payment already feels like a lot to commit to, so “one more payment” can sound impossible before you've even run the numbers. It isn't, once you see the real math and once you break it into pieces you can actually plan for instead of one intimidating lump sum.
What “One Extra Payment a Year” Actually Means
There are two ways to do this and they land in almost the same place mathematically:
● A lump sum, once a year (using a work bonus, tax refund, or a chunk of savings) to send one full extra payment to your lender.
● Spread across the year, dividing that same extra payment into 12 smaller amounts and adding it to every regular monthly payment.
This is also mathematically the same idea behind the well-known “biweekly mortgage payment” strategy: paying half your mortgage every two weeks works out to 26 half-payments a year, which equals 13 full payments instead of 12, the same one extra payment a year, just paid on a different schedule.
The Real Math on a Starter-Home Loan
Let's use a $400,000 loan (close to a typical starter-home payment around $2,500 a month) and look at what one extra payment a year actually does across a realistic range of interest rates.
Rate | Monthly Payment | New Payoff Time | Interest Saved |
6.0% | $2,398 | ~24.8 years | $94,565 |
6.5% | $2,528 | ~24.3 years | $111,979 |
7.0% | $2,661 | ~24.0 years | $131,393 |
7.5% | $2,797 | ~23.6 years | $152,957 |
At 6.5% (close to where many current buyers are landing) that's a mortgage that finishes about 5.7 years early and saves right around $112,000 in interest. That's not far off industry averages: independent analyses of this strategy consistently find that one extra payment a year takes 4 to 6 years off a 30-year loan and saves tens of thousands to well over $100,000, depending on loan size and rate.
These numbers are illustrative, not a promise, your actual savings depend on your loan amount, your rate and when in the loan term you start making extra payments. Extra payments made in the first few years save the most because that's when the biggest share of every regular payment is going toward interest rather than principal.
Turning One Big Payment Into 12 Small Ones
Here's where the math actually gets useful in daily life. Instead of finding one $2,528 payment once a year, you can divide it by 12 and add about $211 to every regular monthly payment. On a $2,500 mortgage payment, an extra $211 a month is a real budget line but it's a much smaller ask than “find an extra $2,500 in December.”
Both paths get you to the same place. Some homeowners prefer the monthly version because it's automatic and doesn't require saving up. Others prefer the once-a-year version because it lines up naturally with a bonus or tax refund and doesn't touch the regular monthly budget at all. Pick whichever one you'll actually stick with, consistency matters more than which method you choose.
When It Might Not Be the Right Move
Extra mortgage payments aren't automatically the best use of extra cash for every homeowner. It may be worth focusing elsewhere first if you:
● Carry high-interest credit card or other consumer debt, that interest rate is almost always higher than your mortgage rate.
● Don't yet have an emergency fund covering several months of expenses.
● Have other long-term investment goals, like retirement accounts, that you haven't fully funded yet.
Every homeowner's financial picture is different, so this is worth thinking through as part of your overall plan, not a decision to make in isolation.
How to Actually Set It Up
● Contact your loan servicer directly and confirm there's no prepayment penalty on your loan.
● Explicitly specify that any extra amount should be applied to principal, not held toward next month's payment, which won't have the same effect.
● If you're spreading it monthly, consider automating the extra amount so it's part of your normal payment and you don't have to remember it each time.
Frequently Asked Questions
How many years does one extra mortgage payment a year actually save?
On a typical 30-year mortgage, one extra payment a year usually saves 4 to 6 years, depending on your loan amount, interest rate and how early in the loan you start.
Is spreading the extra payment monthly the same as paying it all at once?
Very close to the same. Both add roughly one extra full payment to your year; the lump-sum version front-loads it slightly more, so it saves a small amount more in interest, but the difference is minor compared to the overall benefit.
Is paying extra on my mortgage always the right choice?
Not necessarily. If you're carrying high-interest debt or don't have an emergency fund yet, those are usually worth addressing first. For homeowners without those pressures, extra payments are one of the most reliable ways to reduce long-term interest costs.
Thinking About Your Own Numbers?
The exact savings on your loan depend on your specific balance, rate, and timeline (I'm not a financial advisor) so for personalized numbers, a lender or financial planner can run your loan through an amortization calculator. But if you're a first-time buyer trying to figure out what's realistic for your budget, that's exactly the kind of conversation Jeanie Marten Real Estate has every day. Visit MartenTeam.com or book a consultation.
Examples based on a $400,000, 30-year fixed-rate loan and standard amortization math. Actual results vary by loan amount, rate, and timing of extra payments. This is illustrative information, not personalized financial advice.
