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.
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.
One thing extra payments do not do: lower your required monthly payment. For that you need a recast.
Built for US mortgages. Every rate, cost and tax figure below is an editable example you enter — never a live quote.
Refinance decision
- Today
- $2,767/mo
- Rate & term refi
- $2,623/mo
- Break-even
- Month 29
- Staying
- 7 years
Your decision dashboard
Each card shows which scenario leads on one measure over your 7 years planned stay — and what you give up to get it. There is no single best option, because these measures pull against each other.
Lowest monthly payment
Rate-and-term refinance
$2,623/mo all-in
Trade-off: A lower payment usually means a longer term or a bigger balance, which can raise what you pay in total.
Lowest cost over your planned stay
Rate-and-term refinance
$449,929
Trade-off: This counts payments made plus the balance still owed at the end of your stay, minus any cash you received. It can still carry a higher monthly payment.
Fastest payoff
Rate-and-term refinance
25 years
Trade-off: Paying off soonest normally requires the highest monthly outlay and ties up cash you cannot easily get back.
Lowest closing cash needed
Keep current mortgage
$0
Trade-off: Paying little or nothing upfront often means costs are financed into the balance, where they accrue interest.
Scenario by scenario
Keep current mortgage
Change nothing. No closing costs, no new loan, and your existing rate and payoff date stay exactly as they are.
- All-in monthly
- $2,767
- Cost over your stay
- $465,286
- vs keeping your loan
- Baseline
- Break-even
- —
Rate-and-term refinance
Replace your mortgage with a new 25-year loan at 5.75%.
- All-in monthly
- $2,623
- Cost over your stay
- $449,929
- vs keeping your loan
- +$15,357
- Break-even
- Month 29
Full comparison
Every measure, side by side, over the 7 years you expect to stay. Scroll the table sideways on a narrow screen.
| Measure | Keep current | Rate & term refi |
|---|---|---|
| Interest rateThe rate on the new or largest loan in this scenario. | 6.875% | 5.75% |
| Starting loan balance | $320,000Low | $327,500 |
| Starting LTV (loan-to-value) | 71.1% | 72.8% |
| Principal & interest | $2,204 | $2,060Low |
| Extra principalVoluntary principal on top of the scheduled payment. Part of what you pay each month, so it belongs in the all-in figure. | — | — |
| 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 | $2,767 | $2,623Low |
| Total closing costs | NoneLow | $7,500 |
| Cash needed at closingClosing costs paid in cash, plus any lump sum you contribute. | $0Low | $0Low |
| Cash received | None | None |
| Interest over 7 years | $145,286 | $122,429Low |
| Balance left after 7 yearsWhat you would still owe when you expect to sell or refinance again. | $280,138 | $276,862Low |
| Equity after 7 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. | $169,862 | $173,138Low |
| Invested balance after 7 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. | $465,286 | $449,929Low |
| 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 | +$15,357Low |
| Why that differs from interest saved | — | $22,857 less interest, less $7,500 of extra balance you start out owing — leaving you $15,357 better off. |
| Break-even point“Ahead from month 1” means there was no upfront cost to recover. “Never recovers” means the costs are never paid back. | — | Month 29 |
| Simple paybackUpfront 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. | — | No upfront cash to recover |
| Time to payoff | 26 years | 25 yearsLow |
| Total interest, full term | $367,691 | $290,598Low |
| Lifetime cost (interest + costs) | $367,691 | $298,098Low |
How to read this: “Low” marks the lowest figure among the scenarios shown — it 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.
Charts
Mortgage balance over time
What you still owe each month under every selected scenario, including any second lien. The dashed line marks the end of your planned stay.
Cumulative interest paid
Total interest paid to date. A line that flattens has reached payoff. Where lines cross is where one scenario overtakes another on interest.
Break-even: cumulative savings against keeping your mortgage
Above the zero line a scenario has saved you money overall; below it, it has cost you. Each marker is that scenario's break-even month — where its line crosses zero.
Rate & term refi: breaks even in month 29 (2 years 5 months).
What your first monthly payment is made of
Principal and interest is only part of the bill. Property taxes, insurance, mortgage insurance and HOA dues are stacked here at their month-one amounts.
What each scenario actually means
Keep current mortgage
- This is the baseline every other scenario is measured against.
Rate-and-term refinance
- A rate-and-term refinance replaces your entire existing mortgage balance with a new loan. No cash is taken out.
- Closing costs are financed, so you pay interest on them for the life of the loan and your balance starts higher than it is today.
Want the terminology behind these figures? The mortgage glossary defines every term used here, including break-even point, LTV and mortgage recast.
Full amortization schedule
Every payment, month by month: how much goes to interest, how much retires principal, and what you still owe afterwards. Switch to the annual view for a year-by-year summary, or download the full schedule as a CSV that opens in Excel, Google Sheets and Numbers.
| Month | Payment date | Beginning balance | Payment | Principal | Interest | Extra principal | Ending balance | Cumulative interest | Mortgage insurance | LTV |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Jan 01, 2026 | $320,000.00 | $2,204.15 | $370.82 | $1,833.33 | — | $319,629.18 | $1,833.33 | — | 79.9% |
| 2 | Feb 01, 2026 | $319,629.18 | $2,204.15 | $372.94 | $1,831.21 | — | $319,256.24 | $3,664.54 | — | 79.8% |
| 3 | Mar 01, 2026 | $319,256.24 | $2,204.15 | $375.08 | $1,829.07 | — | $318,881.16 | $5,493.61 | — | 79.7% |
| 4 | Apr 01, 2026 | $318,881.16 | $2,204.15 | $377.23 | $1,826.92 | — | $318,503.93 | $7,320.53 | — | 79.6% |
| 5 | May 01, 2026 | $318,503.93 | $2,204.15 | $379.39 | $1,824.76 | — | $318,124.54 | $9,145.29 | — | 79.5% |
| 6 | Jun 01, 2026 | $318,124.54 | $2,204.15 | $381.56 | $1,822.59 | — | $317,742.98 | $10,967.88 | — | 79.4% |
| 7 | Jul 01, 2026 | $317,742.98 | $2,204.15 | $383.75 | $1,820.40 | — | $317,359.23 | $12,788.28 | — | 79.3% |
| 8 | Aug 01, 2026 | $317,359.23 | $2,204.15 | $385.95 | $1,818.20 | — | $316,973.28 | $14,606.48 | — | 79.2% |
| 9 | Sep 01, 2026 | $316,973.28 | $2,204.15 | $388.16 | $1,815.99 | — | $316,585.12 | $16,422.47 | — | 79.2% |
| 10 | Oct 01, 2026 | $316,585.12 | $2,204.15 | $390.38 | $1,813.77 | — | $316,194.74 | $18,236.24 | — | 79.0% |
| 11 | Nov 01, 2026 | $316,194.74 | $2,204.15 | $392.62 | $1,811.53 | — | $315,802.12 | $20,047.77 | — | 79.0% |
| 12 | Dec 01, 2026 | $315,802.12 | $2,204.15 | $394.87 | $1,809.28 | — | $315,407.25 | $21,857.05 | — | 78.8% |
Showing 1–12 of 312 payments
Download any scenario
Each file is generated in your browser — nothing is uploaded. Scenarios with a second lien include a separate block for each loan.
Educational estimates only. Not financial, tax, or lending advice. Every rate here is an example you enter, never a live quote or an offer. Verify loan terms, closing costs, property taxes, insurance and mortgage insurance with qualified providers before deciding.
What different extra payments actually 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.
Notice how non-linear this is. Doubling the extra payment does not halve the term — the early payments do disproportionate work because they attack the balance while it is largest.
Biweekly payments: the same trick with a fee attached
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 — thirteen full payments instead of twelve. That extra payment is the entire effect. It is real, and it is worth roughly four to six years on a 30-year loan.
What it is not is magic, and it does not require a service. Third-party biweekly programs charge setup and per-transaction fees to do something you can do free: divide one monthly payment by twelve and add that amount to your payment each month. Identical result, no fee, and you can stop any month you need to.
Check first that your servicer accepts and applies extra principal on receipt — some hold biweekly halves until a full payment accumulates, which removes the benefit entirely.
When extra payments are not the best use of the money
A guaranteed return equal to your mortgage rate is good. It is not always the best available.
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. Clear those first.
- An emergency fund. Money paid into a mortgage is not accessible again without borrowing against the home. Liquidity has real value.
- Employer retirement matching. A match is an immediate return 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 on the other side: being mortgage-free earlier has value that a spreadsheet does not capture. Both positions are defensible. What is not defensible is making the choice without seeing the numbers — which is what the schedule above is for.
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.
Related calculators
- Refinance & recastThe full eight-scenario comparison: keep, refinance, cash out, HELOC, equity loan, recast, extra principal, or invest the difference.
- AffordabilityWork out a home price from income, debts, cash on hand and your own housing-to-income and debt-to-income ceilings.
- Home equityCompare four ways to turn home equity into cash, side by side.
- Refinance break-evenFind the month a refinance stops costing you money and starts saving it.
- Mortgage recastSee what a lump sum plus a re-amortization does to your required payment.
- Amortization scheduleBuild a full month-by-month table and download it as CSV.