Extra Payment Mortgage Calculator
Model monthly, annual and one-time extra principal payments, and see exactly how many years and how much interest they remove from your mortgage.
Private by design. Your numbers stay on this device.
Educational estimates only. Not financial, tax, or lending advice.
Updated
How much do extra mortgage payments save?
On a typical 30-year mortgage, adding one extra monthly payment per year commonly shortens the loan by four to six years and saves tens of thousands in interest. Adding $200 a month to a $200,000 loan at 6% cuts roughly nine years off the term.
The mechanism is compounding in reverse. Interest each month is charged on the balance that remains, so every dollar of principal you remove eliminates all the future interest that dollar would have generated. That is why the same dollar is worth far more in year two than in year twenty.
Extra payments do not lower your required monthly payment. A recast does that.
Over your 26-year stay
Extra principal leaves your required payment untouched and shortens the loan instead. Every dollar earns your mortgage rate, guaranteed, for as long as the loan would have run.
- Keep current
- Monthly payment
- $2,767
- Net cost over your stay
- $687,691
- vs keeping your mortgage
- —
- Break-even, ours
- —
- Break-even, conventional
- —
- Extra payments
- Monthly payment
- $2,967
- Net cost over your stay
- $605,112
- vs keeping your mortgage
- +$82,579
- Break-even, ours
- Ahead from month 1
- Break-even, conventional
- Nothing upfront to recover
Why two break-even figures? The conventional figure counts only the monthly payment saving against the cash you pay upfront. Ours also counts what you still owe when you sell, which is why the two disagree.
Compared over
the 26 years you expect to stay
Two break-even figures. The conventional figure counts only the monthly payment saving against the cash you pay upfront. Ours also counts what you still owe when you sell, which is why the two disagree.
| Leave it alone | Change your current loan | |
|---|---|---|
| Measure | Keep current | Extra payments |
| Interest rateThe rate on the new or largest loan in this scenario. | 6.875% | 6.875% |
| Starting loan balance | $320,000Low | $320,000Low |
| Starting LTV (loan-to-value) | 71.1% | 71.1% |
| Principal & interest | $2,204Low | $2,204Low |
| Extra principalVoluntary principal on top of the scheduled payment. Part of what you pay each month, so it belongs in the all-in figure. | — | $200 |
| PMI | — | — |
| Property tax + insuranceIdentical across every scenario for the same home, but a real part of the monthly bill. | $563 | $563 |
| Monthly HOA dues | — | — |
| All-in monthly payment | $2,767Low | $2,967 |
| Total closing costs | NoneLow | NoneLow |
| Cash you have to put inClosing costs paid in cash, plus any lump sum or one-time payment this option needs upfront. | NoneLow | NoneLow |
| Monthly commitment on topMoney you have to keep finding every month beyond the required payment: voluntary extra principal, or the same money invested instead. The required payment itself is the all-in figure above. | NoneLow | $200/mo |
| Cash received | None | None |
| Interest over 26 years | $367,691 | $285,112Low |
| Balance left after 26 yearsWhat you would still owe when you expect to sell or refinance again. | $0Low | $0Low |
| Equity after 26 yearsHome value less the balance owed. Uses your assumed appreciation rate, which is 0% unless you change it. It is never used to remove mortgage insurance early. | $450,000Low | $450,000Low |
| Invested balance after 26 yearsOnly the growth on this account is credited against net cost. The contributions are money you paid in, so counting the whole balance would count them twice. | — | — |
| Net cost over your planned stayCash closing costs + payments made + balance still owed − cash received. Excludes property tax, insurance and HOA, which are identical across scenarios. | $687,691 | $605,112Low |
| Savings vs keeping your mortgageThis is not the same as interest saved: it also counts the balance you still owe at the end of your stay and any cash you paid upfront. The row above reconciles the two. | Baseline | +$82,579Low |
| Why that differs from interest saved | — | They agree. |
| Break-even point, ours“Ahead from month 1” means there was no upfront cost to recover. “Never recovers” means the costs are never paid back. | — | Ahead from month 1 |
| Break-even point, conventionalUpfront cash divided by the monthly payment saving. This is the number most people mean by break-even, and it flatters a refinance: it ignores the principal you stop paying down when the term restarts. The equity-adjusted figure above is the one to rank on. | — | Nothing upfront to recover |
| Time to payoff | 26 years | 21 yearsLow |
| Total interest, full term | $367,691 | $285,112Low |
| Lifetime cost (interest + costs) | $367,691 | $285,112Low |
How to read this: “Low” marks the lowest figure among the scenarios shown and is not a recommendation. Net cost counts payments made plus the balance still owed at the end of your stay, minus cash received, which is what makes loans of different sizes and terms comparable.
Full amortization schedule
Every payment, month by month: how much goes to interest, how much retires principal, and what you still owe afterwards. The last money column is the all-in cost (principal, interest, any extra you send, mortgage insurance, property tax, homeowners insurance and HOA dues), which is what leaves your account. Switch to the annual view for a year-by-year summary. Printing and the CSV both follow whichever view you are in, so a year-by-year download gives a year-by-year file, which opens in Excel, Google Sheets and Numbers.
| Month | Payment date | Beginning balance | Payment | Principal | Interest | Extra principal | Ending balance | Cumulative interest | Mortgage insurance | Taxes & insurance | HOA | Total monthly cost | LTV |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Jan 01, 2026 | $320,000.00 | $2,204.15 | $370.82 | $1,833.33 | — | $319,629.18 | $1,833.33 | — | $562.50 | — | $2,766.65 | 71.0% |
| 2 | Feb 01, 2026 | $319,629.18 | $2,204.15 | $372.94 | $1,831.21 | — | $319,256.24 | $3,664.54 | — | $562.50 | — | $2,766.65 | 71.0% |
| 3 | Mar 01, 2026 | $319,256.24 | $2,204.15 | $375.08 | $1,829.07 | — | $318,881.16 | $5,493.61 | — | $562.50 | — | $2,766.65 | 70.9% |
| 4 | Apr 01, 2026 | $318,881.16 | $2,204.15 | $377.23 | $1,826.92 | — | $318,503.93 | $7,320.53 | — | $562.50 | — | $2,766.65 | 70.8% |
| 5 | May 01, 2026 | $318,503.93 | $2,204.15 | $379.39 | $1,824.76 | — | $318,124.54 | $9,145.29 | — | $562.50 | — | $2,766.65 | 70.7% |
| 6 | Jun 01, 2026 | $318,124.54 | $2,204.15 | $381.56 | $1,822.59 | — | $317,742.98 | $10,967.88 | — | $562.50 | — | $2,766.65 | 70.6% |
| 7 | Jul 01, 2026 | $317,742.98 | $2,204.15 | $383.75 | $1,820.40 | — | $317,359.23 | $12,788.28 | — | $562.50 | — | $2,766.65 | 70.5% |
| 8 | Aug 01, 2026 | $317,359.23 | $2,204.15 | $385.95 | $1,818.20 | — | $316,973.28 | $14,606.48 | — | $562.50 | — | $2,766.65 | 70.4% |
| 9 | Sep 01, 2026 | $316,973.28 | $2,204.15 | $388.16 | $1,815.99 | — | $316,585.12 | $16,422.47 | — | $562.50 | — | $2,766.65 | 70.3% |
| 10 | Oct 01, 2026 | $316,585.12 | $2,204.15 | $390.38 | $1,813.77 | — | $316,194.74 | $18,236.24 | — | $562.50 | — | $2,766.65 | 70.3% |
| 11 | Nov 01, 2026 | $316,194.74 | $2,204.15 | $392.62 | $1,811.53 | — | $315,802.12 | $20,047.77 | — | $562.50 | — | $2,766.65 | 70.2% |
| 12 | Dec 01, 2026 | $315,802.12 | $2,204.15 | $394.87 | $1,809.28 | — | $315,407.25 | $21,857.05 | — | $562.50 | — | $2,766.65 | 70.1% |
Showing 1–12 of 312 payments
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Each file is generated in your browser, and nothing is uploaded. Scenarios with a second lien include a separate block for each loan.
The link carries these figures inside it, after the #. That part of a web address is never sent to any server, ours or anyone else’s, so sharing one transmits nothing. Anyone you send it to can read the figures in it.
Educational estimates only. Not financial, tax, or lending advice. Want every option side by side instead? Open the full comparison.
What different extra payments do
Illustrative figures on a $300,000 loan at 6.5% over 30 years.
| Extra payment | Payoff time | Years saved | Approximate interest saved |
|---|---|---|---|
| None | 30 years | — | — |
| $100 per month | ~26 years | ~4 years | ~$60,000 |
| $250 per month | ~22 years | ~8 years | ~$122,000 |
| $500 per month | ~18 years | ~12 years | ~$186,000 |
| One extra payment per year | ~25 years | ~5 years | ~$74,000 |
| $20,000 lump sum in year 1 | ~27 years | ~3 years | ~$77,000 |
Rounded illustrations to show the shape of the effect. Enter your own balance, rate and term above for exact figures and a downloadable schedule.
The effect is not linear. Doubling the extra payment does not halve the term, because the early payments do the most work while the balance is largest.
Biweekly payments
Half the payment every two weeks equals thirteen monthly payments a year.
There are 52 weeks in a year, so paying half your mortgage every two weeks means 26 half-payments, or thirteen full payments instead of twelve. That one extra payment is the whole effect, and it is worth roughly four to six years on a 30-year loan.
You don’t need a service for it. Third-party biweekly programs charge setup and per-transaction fees for something you can do free: divide one monthly payment by twelve and add that amount to your payment each month. The result is the same, there is no fee, and you can stop in any month you need to.
Check first that your servicer applies extra principal when it arrives. Some hold biweekly halves until a full payment builds up, which removes the benefit.
When extra payments are not the best use of the money
A guaranteed return equal to your mortgage rate is good, but other uses of the money can beat it.
Paying down a mortgage returns exactly your interest rate, guaranteed and risk-free. Before committing, weigh it against:
- Higher-rate debt. Credit cards and personal loans almost always cost more than a mortgage, so clear those first.
- An emergency fund. You can’t get money back out of a mortgage without borrowing against the home.
- Employer retirement matching, an immediate return that no mortgage rate competes with.
- A very low rate. At 3% the guaranteed return is modest and safe alternatives may pay more. At 7%, extra principal looks considerably better.
There is also a behavioural argument for paying early: being mortgage-free sooner has value a spreadsheet doesn’t capture. Either choice is reasonable once you have seen the numbers, and the schedule above shows them.
Extra payment questions
- How much does one extra payment a year actually save?
- On a typical 30-year mortgage, adding one extra monthly payment per year commonly shortens the loan by four to six years and saves tens of thousands in interest, depending on the rate and balance. The reason is compounding in reverse: every dollar of principal removed eliminates all the future interest that dollar would have generated.
- Do extra payments lower my monthly payment?
- No. Extra principal shortens the loan; the required payment stays the same. If lowering the required payment is what you need, a recast is the mechanism: it re-amortizes the reduced balance over the remaining term. The two are frequently confused and they produce very different outcomes.
- When are extra payments most effective?
- Early. Interest each month is charged on the remaining balance, so a dollar paid in year two avoids far more interest than the same dollar in year twenty. That said, the interest saved is effectively a guaranteed return equal to your mortgage rate, so compare it against what that money would earn elsewhere and against higher-rate debt.
- Will my servicer apply extra money to principal automatically?
- Not always. Some servicers hold extra amounts as a prepaid future payment rather than applying them to principal, which produces none of the benefit. Check your servicer's instructions and confirm on your next statement that the balance dropped by the amount you sent.