Extra Mortgage Payment Calculator
The Extra Mortgage Payment Calculator shows how paying more than your required monthly payment shrinks the interest you owe and shortens your loan. Enter your balance, rate, and term, then add an extra amount to see the interest saved and how many years and months earlier you pay off the mortgage.
It is built for homeowners weighing an early-payoff plan: people thinking about an extra fixed amount each month, an annual lump sum from a bonus or tax refund, or both at once. Every result updates instantly, with a side-by-side comparison against your original schedule so the trade-off is easy to read.
How to Use the Calculator
Enter your loan details
Set the Loan Amount (your remaining balance or original loan), the Interest Rate, and the Loan Term. Drag a slider or type a value directly, and use the term presets — 10, 15, 20, or 30 years — for one-tap selection.
Add your extra payments
Enter an Extra Monthly Payment added to every payment, an Extra Yearly Payment applied once a year for bonuses or tax refunds, or both together for the largest impact.
Review interest and time saved
See your Interest Saved and Time Saved at a glance, with the Original vs Extra Payments comparison showing total interest, total amount paid, and payoff time for each plan.
Open the amortization schedule
Expand the Amortization Schedule for a year-by-year breakdown of principal, interest, and remaining balance, so you can see exactly when the loan is paid off.
Features
Extra Monthly Payments
Add a fixed amount to every monthly payment and watch the interest saved and payoff time update in real time.
Extra Yearly Payments
Model an annual lump sum — applied once each year — that fits bonuses, tax refunds, or other yearly windfalls.
Combined Payment Analysis
Use monthly and yearly extras together to see the full combined effect on your total interest and loan term.
Original vs Accelerated Comparison
A side-by-side view of total interest, total amount paid, and payoff time for your original schedule versus the extra-payment plan.
Visual Interest Breakdown
A color-coded bar shows the share of interest you still pay versus the share you save, with clear percentage labels.
Year-by-Year Amortization Schedule
Expand a yearly breakdown of principal paid, interest paid, and remaining balance to pinpoint your payoff milestones.
Sliders, Inputs & Term Presets
Drag a slider or type a value directly, and pick a 10-, 15-, 20-, or 30-year term in one tap. Results recalculate instantly.
Multi-Currency Support
Switch currencies and every figure reformats with the right symbol and thousand separators automatically.
Automatic Overpay Protection
When an extra payment exceeds the remaining balance, it is capped to the exact amount left, so you never overpay.
Responsive with Dark Mode
A clean layout that adapts to any screen size and includes a built-in dark theme.
Frequently Asked Questions
How much can extra payments save on a mortgage?
It depends on your balance, rate, and how much extra you pay. As an example, on a $300,000 loan at 6.5% over 30 years, an extra $200 per month can save tens of thousands in interest and clear the loan several years early. Enter your own figures to see your exact interest saved and time saved.
Is it better to make one lump sum or monthly extra payments?
Extra monthly payments tend to be slightly more effective because they reduce the principal sooner, so less interest accrues each month. A yearly lump sum from a bonus or tax refund still helps a lot. The calculator lets you enter monthly extras, yearly extras, or both, so you can compare the approaches directly.
Does my extra payment go entirely toward principal?
In this calculator, yes. Your regular payment covers that month's interest plus some principal, and any extra you add is applied straight to the principal balance, which lowers the interest charged in every following month.
Are there prepayment penalties for paying my mortgage early?
That depends on your lender. Some mortgages carry prepayment penalties, often in the early years of the loan. This tool shows the mathematical savings only — check your loan agreement or ask your lender before committing to an extra-payment plan.
How is the amortization schedule calculated?
The calculator uses the standard amortization formula to find your fixed monthly payment, then simulates the loan month by month. Each month it charges interest on the remaining balance and puts the rest of the payment — including your extras — toward principal. Yearly extra payments are applied once every twelve months.
What happens if my extra payment exceeds the remaining balance?
The payment is automatically capped at the balance that is left, so the loan simply finishes in that final month and you never overpay.
Is my loan data stored anywhere?
No. Every calculation runs locally in your browser. Your loan amount, interest rate, and payment figures are never sent to a server or saved anywhere.
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