One extra payment typically shortens your loan by one month to several months, depending on your loan size and how far into the loan you are
The exact time saved is not the same for everyone. A single extra payment early in a 30-year mortgage saves more time than the same payment made near the end. The reason is that early payments reduce the principal balance when interest is still being calculated on a larger amount, so each dollar of principal saves more in future interest.
To find your specific number, you need three pieces of information: your current loan balance, your interest rate, and how many payments remain. Your loan servicer can tell you all three. Once you have those numbers, an amortization calculator (a free tool available from most banks' websites) can show you the exact payoff date with and without the extra payment.
The savings also depend on when you make the extra payment. A payment made in January saves more time than the same payment made in December of the same year, because the earlier payment starts reducing your balance sooner.
Key Takeaways
- One extra payment made early in your loan can shorten it by several months; the same payment made near the end may shorten it by only weeks.
- The time saved depends on your loan balance, interest rate, and how many payments you have left — not just the payment amount.
- An amortization calculator can show you the exact payoff date before and after an extra payment, using information from your loan documents.
- Making extra payments consistently (such as one per year) saves more time than making a single extra payment once.
Why the time saved varies so much
On a standard 30-year mortgage, you pay mostly interest in the early years and mostly principal in the later years. This is because your interest payment is calculated on the remaining balance each month. When the balance is large, the interest portion of your payment is large, and the principal portion is small. As the balance shrinks, the interest portion shrinks and the principal portion grows.
An extra payment goes entirely to principal, because you have already paid that month's interest. When you make an extra payment early in the loan, you are reducing a large balance, which means you avoid paying interest on that amount for the remaining 25 or 29 years of the loan. When you make the same payment near the end, you are reducing a small balance, so you avoid interest for only a few months.
For example, an extra $500 payment made in year 2 of a 30-year loan might save you 4 to 6 months of payments. The same $500 payment made in year 28 might save you only 2 to 3 weeks. The payment amount is identical, but the time saved is very different because of when the balance was reduced.
How to calculate the time saved for your specific loan
Start by gathering three numbers from your mortgage statement or loan servicer: your current principal balance (not the payment amount, but the total you still owe), your interest rate, and the number of payments remaining. Your servicer's website usually shows all three in the loan summary section.
Next, use an amortization calculator. Most banks offer free calculators on their websites; Bankrate, NerdWallet, and Investopedia also have them. Enter your current balance, interest rate, and remaining term. The calculator will show you your current payoff date. Then change the remaining term by one month (or enter a one-time extra payment if the calculator has that option) and run it again. The difference between the two dates is the time your extra payment saves.
If you want to see the effect of making one extra payment per year instead of just once, you can adjust the monthly payment amount upward by dividing your extra payment by 12. For example, if you plan to make one $1,200 extra payment per year, add $100 to your regular monthly payment in the calculator and see how many months that saves.
The difference between paying once and paying consistently
One extra payment saves time. Twelve extra payments (one per month) save much more time — often several years off a 30-year loan. The compounding effect matters: each extra payment reduces the balance, which reduces next month's interest, which means more of next month's regular payment goes to principal, which reduces the balance further.
Many people find it easier to make one extra payment per year (often with a tax refund or bonus) than to increase their monthly payment. One extra payment per year typically saves 2 to 5 years off a 30-year mortgage, depending on the loan size and interest rate. Making extra payments every month saves 5 to 10 years.
The key is consistency. A single extra payment made once has a real but modest effect. Extra payments made year after year compound into significant time and interest savings.
What changes the amount of time saved
Loan size: A larger loan balance means more interest is being paid, so an extra payment saves more in total interest dollars. However, the time saved (in months) is roughly the same whether your loan is $200,000 or $400,000, because the percentage reduction in the balance is what matters.
Interest rate: A higher interest rate means more of each payment goes to interest rather than principal. An extra payment on a 6% loan saves more time than the same payment on a 3% loan, because the interest being avoided is larger.
How far into the loan you are: This is the biggest factor. An extra payment in year 1 saves far more time than the same payment in year 25, for the reasons explained above.
Loan term: An extra payment on a 15-year loan saves less time (in months) than the same payment on a 30-year loan, because the balance is being paid down faster already and the remaining term is shorter.
When an extra payment makes the most difference
The best time to make extra payments is as early as possible in your loan. If you have just closed on a mortgage, even small extra payments now will save months or years. If you are in year 20 of a 30-year loan, an extra payment still helps, but the time saved will be measured in weeks rather than months.
That does not mean you should not make extra payments late in the loan. Every dollar of principal you pay reduces the amount of interest you will pay going forward. But if you are deciding between making extra mortgage payments and other financial goals — like building an emergency fund or paying down higher-interest debt — the timing of your mortgage in its life cycle is worth considering.
If you have a very low interest rate (below 3%), the time saved by extra payments is smaller, and you might get better returns by investing the money instead. If you have a higher rate (above 5%), extra payments save more time and money, making them a stronger choice.
Frequently Asked Questions
Does making one extra payment per year really save years off my mortgage?
Yes, typically 2 to 5 years on a 30-year loan, depending on your interest rate and how early you start. The effect is larger if you start in the first few years of the loan. An online amortization calculator can show you the exact number for your loan.
What if I make an extra payment but then stop — does it still help?
Yes. One extra payment reduces your balance permanently, which reduces the interest you pay for the rest of the loan. You do not need to make extra payments every month for the first one to matter.
Is it better to make one big extra payment or split it into smaller ones throughout the year?
Splitting it into smaller payments saves slightly more time, because each payment reduces the balance sooner and starts saving interest when ready. The difference is usually small — a few weeks — but mathematically, earlier is always better.
How do I know if my loan allows extra payments without a penalty?
Check your loan documents or call your servicer. Most mortgages allow extra principal payments with no penalty, but some older loans or specific loan types may have restrictions. Your servicer can confirm in one call and tell you how to make sure the extra payment is applied to principal, not held as a future payment.
Will an extra payment lower my monthly payment amount?
No. An extra payment shortens the loan but does not change your monthly payment. You will continue paying the same amount each month until the loan ends earlier than originally scheduled.