Why do earlier overpayments often help more?

Reducing capital earlier means less balance remains to attract interest in later months.

Can I overpay any amount?

Not necessarily. Many mortgage deals have annual overpayment limits or early repayment charges.

Should I use savings to overpay?

That is a wider financial decision involving emergency cash, savings interest, debt rates and personal priorities. The calculator only shows the mortgage effect.

Mortgages

Mortgage Overpayment Calculator

Overpayments can be powerful because reducing the balance also reduces future interest. The trade-off is that money used to overpay is no longer available as cash.

Free calculatorInputs saved only in this browser

Your estimate

Use the result as a planning guide and change inputs to test the assumptions that matter most.

How this calculator works

The calculator builds a baseline amortisation schedule, then compares it with the same mortgage after your selected lump sum and/or monthly overpayment.

How to use it

Enter the current mortgage balance, interest rate and remaining term.
Enter your current payment if known, or leave it blank to derive a standard repayment.
Add a monthly overpayment and/or one-off lump sum.
Compare the new payoff date and total interest with the baseline.

Assumptions and limitations

Check your lender’s overpayment allowance and any early repayment charge before acting. Assumes the entered rate remains unchanged throughout the model.