Mortgage Repayment Planner (Lump Sum & Refinance)

Enter the loan principal, rate, and term, then layer bonus repayments, ad-hoc prepayments, and a refinance scenario to understand how each choice changes the payoff date, total interest, and monthly burden.

More languages: ja | en | zh-CN | es | fr | de | it | ko | pt-BR

Loan Basics

Bonus Payments

Hold Ctrl (Cmd on Mac) to select multiple months.

Lump-sum Prepayments

Add one-off prepayments (up to 5 entries) to shorten the term or lower later payments.

Refinance Scenario

Summary

No. Month Payment Principal Interest Extra Balance

FAQ

What is the difference between equal payment and equal principal?

Equal payment keeps the monthly payment (principal + interest) constant, whereas equal principal keeps the principal portion fixed and gradually reduces the monthly payment. This calculator lets you toggle both methods for comparison.

How are lump-sum prepayments and refinancing reflected?

Lump-sum prepayments reduce the outstanding principal on the selected month and you can choose whether to shorten the term or lower future payments. The refinance comparison recomputes the remaining balance with the new rate, term, and fees to show the cost difference.

Is the APR nominal or effective? How is compounding handled?

Use the nominal annual rate split into r = APR/12 for the schedule. If your lender quotes an effective APR including compounding/fees, approximate by using the per‑period rate and adjusting periods accordingly.

Can I change the payment frequency (biweekly, weekly)?

Not built in. Convert APR to a per‑period rate (e.g., biweekly APR/26) and set the number of periods accordingly, or generate an amortization schedule and aggregate payments at that cadence.

Related calculators