Free browser tool

Free Mortgage Extra Repayments Calculator

Compare regular mortgage payments with extra repayments and a lump sum. See interest saved, time saved and remaining balances. Free, local and no signup.

Quick answer

What mortgage extra repayments calculator does

Extra repayments reduce the amount of principal on which later interest is calculated. This calculator first computes the repayment needed to amortize the entered balance across the remaining term. It then runs a second schedule with the same regular payment, adding your recurring extra and optional lump sum. It caps the final repayment so you do not pay more than the balance and accrued period interest. The baseline uses the same rate and payment frequency.

Mortgage extra repayments calculator comparing loan balances, interest saved and payoff time – KnowledgePilot.

How to use this tool

Enter the outstanding balance, fixed annual rate and remaining term using one currency consistently.
Choose repayment frequency, the extra amount per repayment and an optional one-off lump sum.
Compare total interest and payoff time with the baseline, then inspect the balance schedule.

Worked example

For a zero-interest balance of 1,200 over one year with monthly repayments, the regular payment is 100. Paying an extra 100 each month clears the loan in six payments rather than twelve. At positive interest, reducing principal earlier can also reduce total interest.

What to check before using the result

This is an equal-period approximation, not a lender quote. Monthly, fortnightly and weekly schedules use 12, 26 and 52 periods per year, with the annual rate divided by that count. Some lenders accrue interest daily and use different conventions. Fixed-rate fees, early repayment limits, offset balances, redraw, taxes and future rate changes are excluded. Check whether your lender applies extra payments directly to principal. A lump sum scheduled after payoff is unused. Not financial advice.

Good to know

Frequently asked questions

Is this tool free and does it use AI?

It is free without an account. It uses fixed parsing rules, formatting or arithmetic in your browser, without AI or paid API calls. KnowledgePilot’s AI summarizers are separate products.

Does my text or file leave this device?

Inputs and document files are processed locally. This tool does not upload your text or files to KnowledgePilot. Optional saved drafts stay in your browser, so download a copy before clearing its data.

Can I rely on the result without checking it?

Review the worked example and limits above. The output follows the information you enter; it does not verify the source or supply missing facts. Check important details against the original material.

Source guidance

ASIC Moneysmart: mortgage calculator and assumptions

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