Example result based on the prefilled values.
Current Payment
$1,238.20
Payment With Monthly Overpayment
$1,438.20
Payoff Term
15.00 years 7.00 months
Months Saved
54.00
Interest Saved
$29,062.14
Continue your plan
Useful next calculations
When to use this calculator
- Before comparing lenders, brokers, or repayment options.
- When you want to test how a different deposit, rate, or term changes affordability.
- When you need a quick estimate before using a formal quote or agreement in principle.
- When you are stress-testing your budget against a potential rate rise to see the impact on monthly payments.
- When you want to understand the full cost of borrowing — not just the monthly figure — before you commit.
A realistic US planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Remaining Balance ($)
$280,000
Interest Rate (%)
5%
Remaining Term (Years)
25 years
Monthly Overpayment ($)
6
After entering these figures, review current payment, payment with monthly overpayment and payoff term together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Current Payment
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Payment With Monthly Overpayment
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Payoff Term
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Months Saved
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Interest Saved
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator compares a baseline repayment projection with a plan that adds the monthly and one-off overpayments you enter. It keeps the calculated contractual repayment constant and applies the one-off amount before the monthly projection; the payoff term and interest saving are therefore estimates rather than instructions to your lender. A lender may instead reduce your required payment, credit an overpayment at a different point, or apply product-specific rules.
The projection assumes a constant interest rate and does not model early repayment charges, rate changes, payment holidays, offsets or fees. Check your lender's overpayment allowance, any early repayment charge and how it will apply a lump sum before paying.
Official references
Common mistakes
- !Using an assumption that is not supported by a current local quote, bill, statement or official source.
- !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
- !Mixing monthly and annual inputs without converting them consistently.
- !Forgetting location-specific taxes, fees, eligibility rules or payroll deductions where they apply.
- !Testing only one scenario instead of checking how a cautious assumption changes the result.
What to do next
- Run a second scenario with a cautious assumption so you can see the downside clearly.
- Compare the result with the related calculators below before making a decision.
- Check current local rules, eligibility and provider terms before applying or committing money.
- Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.
- Use the result to prepare better questions for a lender, provider, adviser or employer rather than treating it as a final answer.
Frequently asked
Use arrow keys to navigate items, Enter or Space to expand/collapse.