Extra Payments Calculator
See how extra principal payments shorten payoff and cut total interest—monthly, annual, or one-time.
Enter your plan below. Results update instantly.
Loan
Extra payments
Key results
Amortization with extras (first 12 months)
| Month | Start Balance | Interest | Principal | Extra | End Balance |
|---|---|---|---|---|---|
| Enter a loan amount to see your schedule. | |||||
Annual summary
| Year | Interest | Principal | Extra | Ending Balance |
|---|---|---|---|---|
| Enter a loan amount to see yearly totals. | ||||
How the Extra Payments Calculator Works
The calculator uses the standard fixed-rate mortgage math to compute your baseline monthly principal-and-interest (P&I) payment. Then it simulates each month of your loan, applying any extra principal (monthly, annual, or one-time) directly to the balance. Lower balance ⇒ less interest next month ⇒ a shorter payoff timeline.
The basic math
Monthly P&I = P × ( r × (1 + r)^n ) / ( (1 + r)^n − 1 )
Where:
P = loan amount (principal)
r = monthly rate (APR ÷ 12)
n = total payments (years × 12)What the results mean
- New payoff date: When your loan would end if you follow the extra-payment plan.
- Time saved: Months shaved off compared with the baseline schedule.
- Interest saved: The reduction in lifetime interest versus making no extras.
- Total extra paid: The total of all extra principal you contributed.
Calculations are estimates for planning and education. Actual schedules may vary by servicer rules and rounding.
Benefits of Making Extra Payments
- Save interest: Every dollar sent to principal is a dollar that stops accruing interest going forward.
- Pay off sooner: Extra principal advances you through the amortization schedule faster.
- Build equity quicker: A lower balance increases your ownership share and may remove PMI sooner on conventional loans.
Important Considerations Before Making Extra Payments
- Prepayment penalties: Rare on modern owner-occupied loans but do exist on some products. Confirm with your lender/servicer.
- Order of priorities: High-interest debts and an adequate emergency fund often come first.
- Cash flexibility: Once sent to principal, cash isn’t easily withdrawn; weigh liquidity needs.
- Servicer instructions: Mark payments “Apply to principal only” to avoid them being treated as future installments.
Strategies to Pay Off Your Mortgage Early
- Round up the payment: Add a steady amount (e.g., $50–$200) to P&I each month.
- One extra payment per year: Paying the equivalent of one extra monthly P&I annually can shave years off a 30-year loan.
- Bi-weekly schedule: 26 half-payments ≈ 13 full payments per year; confirm your servicer applies bi-weekly funds promptly to principal.
- Lump-sum payments: Tax refunds, bonuses, or windfalls applied to principal provide an outsized impact when paid earlier in the term.
Example Scenarios
Try these in the calculator to see the effect on your payoff date and total interest:
- +$100 per month: A small recurring extra can cut many months from a 30-year term.
- $5,000 lump sum in year 2: Early lump sums are powerful because they reduce the balance for many remaining months.
- One extra payment per year: Enter your base P&I as an annual extra and compare.
Your results depend on rate, remaining term, and how early the extra is applied.
Frequently Asked Questions
How does the extra payment calculator work?
It computes your standard P&I and then simulates month by month with your extra plan applied to principal. You’ll see a new payoff date, time saved, and interest saved versus the baseline.
Is a lump sum or monthly extra better?
Earlier reductions generally save more interest. A single early lump sum saves more than the same total paid late. But a consistent monthly extra is often easier to maintain.
Can extra payments change my escrow?
No. Escrow collects for taxes and insurance. Extra principal only affects your loan balance and interest.
What about refinancing instead of extra payments?
Refinancing can reduce payment and interest if your new rate and costs justify it. Use our calculator on the homepage to compare current payments, then consider a refi analysis if rates or terms are favorable.
How do I ensure extra funds go to principal?
Follow your servicer’s payment instructions and memo your online payment as “apply to principal only.” Check the next statement to confirm application.