Finance calculator
See how much interest and time you save by adding extra monthly payments to your mortgage principal.
Remaining principal balance.
Your current mortgage interest rate.
Years left on your mortgage.
Additional amount applied to principal each month.
Total Interest Saved
$98,473
Formula verified 9 September 2026
Months Paid Off Early
74
New Payoff Timeline (months)
262
Interest Without Extra Payments
$385,045
Regular Monthly Payment
$2,038.83
Estimate only — not financial advice; lender terms, fees, and taxes vary. Read the full disclaimer ↓
Year-by-year balance for the regular schedule versus the same loan with your extra monthly payment, using the same amortization logic as the calculator above. The accelerated loan reaches zero sooner.
| End of year | Balance (no extra) | Balance (with extra) |
|---|---|---|
| Year 1 | $296,421 | $293,942 |
| Year 2 | $292,583 | $287,446 |
| Year 3 | $288,467 | $280,481 |
| Year 4 | $284,054 | $273,012 |
| Year 5 | $279,322 | $265,004 |
| Year 6 | $274,248 | $256,416 |
| Year 7 | $268,807 | $247,207 |
| Year 8 | $262,973 | $237,333 |
| Year 9 | $256,717 | $226,745 |
| Year 10 | $250,009 | $215,392 |
| Year 11 | $242,815 | $203,218 |
| Year 12 | $235,102 | $190,163 |
| Year 13 | $226,832 | $176,165 |
| Year 14 | $217,963 | $161,156 |
| Year 15 | $208,453 | $145,061 |
| Year 16 | $198,256 | $127,802 |
| Year 17 | $187,321 | $109,296 |
| Year 18 | $175,597 | $89,452 |
| Year 19 | $163,024 | $68,174 |
| Year 20 | $149,543 | $45,358 |
| Year 21 | $135,087 | $20,892 |
| Year 22 | $119,586 | Paid off |
| Year 23 | $102,965 | Paid off |
| Year 24 | $85,142 | Paid off |
| Year 25 | $66,030 | Paid off |
| Year 26 | $45,537 | Paid off |
| Year 27 | $23,563 | Paid off |
| Year 28 | $0 | Paid off |
Estimates only — not financial, tax, or professional advice.
100% private — every number you enter is calculated in your browser and never sent to our servers.
What it calculates: Total Interest Saved, Months Paid Off Early, New Payoff Timeline (months), Interest Without Extra Payments.
Updated 5 June 2026 · Transparent assumptions
Calculate standard amortization schedule for base payment.
$300K at 7%, 28 years left, $200/month extra.
Regular Payment
$2,039
Interest Without Extra
$385,045
Interest Saved
~$98,473
Paid Off Early
74 months (6.2 years)
Adding $200 a month to the principal pays the loan off about 6.2 years sooner and saves roughly $98,000 in interest, because every extra dollar removes balance that would otherwise accrue interest for years.
This tool shows what happens when you add a fixed amount to your mortgage principal every month. It estimates how much interest you avoid and how many years earlier the loan is paid off.
It is helpful when you have spare cash flow and want to compare the value of putting it toward the mortgage rather than leaving the loan on its original schedule.
First the calculator finds your regular payment from the balance, rate, and remaining term. It then adds your extra amount to that payment and works out how many months it now takes to reach a zero balance.
Because the extra goes straight to principal, the balance falls faster than scheduled, and the amortization formula returns a shorter payoff period. The interest saved is the difference between total interest on the original schedule and the accelerated one.
Two figures stand out: the interest saved and the time saved. The interest saved is real money you keep; the months saved show how much sooner you own the home outright.
The year-by-year table makes the gap visible. Early on the two balances look similar, but the accelerated column pulls ahead steadily and reaches zero while the regular loan still has years to run.
A common slip is assuming extra payments lower the required monthly amount. They do not; they shorten the term while the scheduled payment stays the same.
Another is sending extra money without instructing the servicer to apply it to principal. If it lands as a prepaid future installment instead, the interest savings shown here will not materialize.
Extra payments do the most good early, when the balance and the interest it generates are largest. Even small amounts in the first years can outperform larger amounts later.
Before committing, make sure you have an emergency fund and no higher-interest debt. Money locked into home equity is harder to reach than cash in a savings account.
The model assumes a fixed rate and a constant extra payment. It does not account for prepayment penalties, escrow changes, or refinancing partway through.
Figures are estimates for general guidance, not financial advice. Confirm your loan terms with your servicer and consider a qualified professional when weighing payoff against other goals such as investing or retirement saving.
It depends on your guaranteed mortgage rate versus your expected after-tax investment return. Paying down a mortgage is a risk-free return equal to the rate, while investing may earn more but is not guaranteed. Many people split the difference, and the emotional value of being debt-free also weighs in.
Interest is charged on the outstanding balance. An extra payment reduces that balance immediately, so every future month accrues interest on a smaller amount. Early in the loan, when the balance is largest, that effect compounds into large savings over the remaining term.
No. On a standard mortgage, extra principal shortens the term rather than reducing the required monthly payment. You keep paying the same amount but finish sooner. To lower the payment itself you would need to refinance or ask about a recast.
A recast re-amortizes your loan over the remaining term after you make a large lump-sum payment, which lowers the monthly payment while keeping the same rate and payoff date. It is different from extra monthly payments, which shorten the term instead.
Yes. Tell your servicer to apply any extra amount to principal, not to the next scheduled payment. If it is credited as a future payment instead, you will not get the interest-saving benefit this calculator assumes.
Most modern mortgages allow extra payments freely, but some loans charge a penalty for paying off early within a set window. Check your loan documents or ask your servicer before committing to a payoff strategy.
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Finance disclaimer
Results are estimates based on the figures you enter and standard formulas. Rates, fees, taxes, and lender terms vary and change over time, so confirm important numbers with your lender or a qualified professional. This is educational information, not financial advice.
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Published 9 September 2026