Loans & borrowing · Free calculator
Extra Payment Loan Calculator
See how an extra monthly principal payment changes your payoff time and interest, with a downloadable schedule.
01 / Set your scenario
Your inputs
02 / Review your estimate
Estimated results
Change the inputs to explore a different scenario.
Method and limitations
Extra payments are applied monthly after accrued interest, with no prepayment charges. The model keeps the normal payment unchanged and reduces the payoff time.
Assumes fixed rates and regular monthly periods. Actual lender schedules can use daily interest, rounding, different payment allocation, fees or penalties. Confirm the contract and a current payoff quote before acting.
Continue with the related borrower guide or return to all loan guides and calculators.
Educational estimate, not financial advice or a loan offer. No credit decision is made. Inputs are processed in your browser and are not submitted by this calculator. See the financial disclaimer.
Default examples use US dollars. Default rates and balances are hypothetical examples.
Adjust the inputs, then select Calculate to review your scenario.
Method, assumptions and result checks
What this tool covers: See how an extra monthly principal payment changes your payoff time and interest, with a downloadable schedule.
A standard monthly amortizing-loan payment is P × r ÷ [1 − (1 + r)−n], where P is principal, r is the annual note rate divided by 1,200 and n is the number of monthly payments. At zero interest, payment is P ÷ n. Fees, extra payments and rate changes depend on the specific options and method described on this page.
Review the calculator’s worked examples, formulas, timing and exclusions in the sections below. Input units and payment frequency matter. A displayed APR is not necessarily the interest rate used by the model. Tax, investment, daily-interest and specialist loan models have different rules.
Interface and accessibility reviewed November 8, 2026. This is not a certification of current rates, tax tables or every financial statement. Verify important results against actual documents.
Monthly loan formulas and worked examples · Build questions for your lender
See how an extra monthly principal payment changes your payoff time and interest, with a downloadable schedule.
Learn more about this calculation
Review these related guides before comparing estimates with actual lender terms.
How to use this calculator & related guidance
Compare a repeatable payment, not an optimistic month
Use an amount you can maintain after essential expenses and a cash reserve. The normal installment stays unchanged; extra money reduces principal after interest. Compare the saved example with a smaller extra amount and inspect the complete final payment.
Use the result in three steps
- Copy the amounts, contract rates and dates from the actual offer. The presets are invented examples.
- Save a baseline, change one assumption and compare results. Inspect the full schedule where available.
- Use Verify to check the software arithmetic, then export the current scenario. Self-checks do not verify your contract or eligibility.
Key takeaways before using this estimate
- This model keeps the required installment unchanged and shortens the term. A lender-approved payment recalculation is a different arrangement. Confirm the treatment of extra money and any charge before acting.
- The last payment is capped at the remaining principal plus that period’s interest. The schedule therefore does not assume a full extra payment after the balance has already been cleared.
- CSV and PDF use the last valid scenario. Display currency relabels amounts without converting exchange rates.
Frequently asked questions
Will my required payment fall?
This model keeps the required installment unchanged and shortens the term. A lender-approved payment recalculation is a different arrangement. Confirm the treatment of extra money and any charge before acting.
Why is the final payment smaller?
The last payment is capped at the remaining principal plus that period’s interest. The schedule therefore does not assume a full extra payment after the balance has already been cleared.
Guides that use this calculator
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