See exactly how much interest you save and how many years early you pay off your mortgage or loan by making extra payments — monthly, yearly or a one-time lump sum.
Enter your loan details and extra payment amount, then hit Calculate to see your savings.
Outstanding loan balance — standard vs. with extra payments
| Month | Payment | Principal | Interest | Extra | Balance |
|---|
Click any scenario below to instantly load it into the calculator and see the results.
$300,000 at 6.5% — the most common US mortgage scenario
$400,000 at 7.0% — typical for recent homebuyers
$300,000 at 6.5% — pay one extra full payment annually
$250,000 at 6.0% — aggressive payoff strategy
$30,000 at 7.5% for 5 years — typical auto loan
$300,000 at 6.5% — one-time windfall applied immediately
The savings from extra mortgage payments are often surprising — even a modest extra payment made consistently delivers disproportionately large interest savings because of how amortization works. Every dollar of extra principal you pay today reduces every future month's interest charge for the rest of the loan.
The table below shows interest savings and time saved for a $300,000 mortgage at 6.5% for 30 years (standard monthly payment: $1,896.20) at various extra monthly payment levels:
| Extra/Month | Total Extra Paid | Interest Saved | Time Saved | New Payoff Time | Return on Extra $ |
|---|---|---|---|---|---|
| $50/mo | ~$20,000 | $32,810 | 1 yr 7 mo | 28 yrs 5 mo | ~1.6× ROI |
| $100/mo | ~$34,000 | $55,150 | 3 yrs 1 mo | 26 yrs 11 mo | ~1.6× ROI |
| $200/mo | ~$58,000 | $98,890 | 5 yrs 8 mo | 24 yrs 4 mo | ~1.7× ROI |
| $300/mo | ~$75,600 | $134,240 | 7 yrs 10 mo | 22 yrs 2 mo | ~1.8× ROI |
| $500/mo | ~$109,000 | $186,710 | 10 yrs 11 mo | 19 yrs 1 mo | ~1.7× ROI |
| $1,000/mo | ~$168,000 | $269,100 | 15 yrs 8 mo | 14 yrs 4 mo | ~1.6× ROI |
Notice that in every row above, the interest saved is greater than the total extra principal paid. This is the compounding power of early principal reduction — every dollar you pay ahead of schedule eliminates multiple dollars of future interest. Use the calculator above with your own numbers to see your personal savings.
When you make an extra payment on a fixed-rate mortgage or loan, the extra amount goes entirely toward reducing your outstanding principal balance. Your required monthly payment stays exactly the same — it is not reduced.
What changes is what happens the following month. Because interest is calculated as Balance × monthly rate, a lower balance means a lower interest charge. With less of your fixed payment consumed by interest, more goes to principal — which lowers the balance further the next month, and so on. This snowball effect is why consistent extra payments save such a large amount of interest over time.
Crucially, you can stop making extra payments at any time without penalty (on most US mortgages). Extra payments give you flexibility that refinancing to a shorter term does not — if your income drops, you simply stop the extra payments and revert to the regular payment.
When you make an extra payment by check, online transfer, or over the phone, explicitly instruct your lender or servicer to apply the extra amount to principal, not to your next month's payment. Some servicers will otherwise treat extra funds as an advance on your next scheduled payment, which does not reduce your principal the same way and saves you less money.
The three most common extra payment strategies each have different advantages:
The most powerful strategy over time because the benefit starts immediately and compounds every month. Even a small consistent extra payment — $100, $200, $300 — adds up to enormous savings over a 30-year loan. The downside is that it requires consistent cash flow discipline.
Ideal if you receive a predictable annual bonus, tax refund, or other lump sum. One extra full mortgage payment per year is the equivalent of switching from 12 payments to 13 payments annually, cutting roughly 4–5 years from a 30-year mortgage. It is often easier psychologically to commit to one large annual payment than to a monthly commitment.
The best strategy when you receive a windfall — inheritance, home sale proceeds, investment payout, or settlement. The earlier in the loan you make a lump sum payment, the greater the savings, because the principal reduction eliminates interest charges for decades to come. A $20,000 lump sum applied in month 1 of a $300,000 mortgage saves over $55,000 in interest.
This is one of the most common personal finance questions, and the right answer depends on your individual situation. Here are the key factors to consider:
Arguments for extra mortgage payments: Guaranteed, risk-free return equal to your mortgage rate. Builds home equity faster. Psychological peace of mind from debt reduction. Mortgage interest deduction phase-outs make it less valuable for many borrowers. No tax on the "return" from interest saved.
Arguments for investing instead: Stock market has historically returned 7–10% annually over long periods, potentially higher than your mortgage rate. Tax-advantaged accounts (401k, IRA) let you compound gains without paying tax annually. Mortgage interest may still be deductible. Liquidity — invested money is accessible; equity in your home is not without refinancing or selling.
If your mortgage rate is above 6%, the guaranteed return from paying it down often competes favorably with after-tax investment returns, especially in tax-deferred accounts you've already maxed out. If your rate is below 4–5%, investing the extra money in a diversified portfolio has historically outperformed over most 20–30 year periods. Between 5–6%, it's a close call that depends on your risk tolerance and tax situation. Always consult a financial advisor for personalized guidance.