Cashback Remortgages · Mortgage calculations
Mortgage Overpayment Calculator
Compare a standard repayment schedule with an extra monthly payment, an immediate lump sum, or both. The illustration keeps the original standard payment and shortens the term; your lender may apply overpayments differently.
Your overpayment illustration
The starting 5% is a calculation example, not a current lender offer. Enter the rate you want to compare.
- Standard monthly repayment
- £1,461.48
- Illustrated interest reduction, before charges
- £25,381.91
- Illustrated term reduction
- 2 years 11 months
- Remaining illustrated term
- 22 years 1 month
Repayment mortgage with monthly payments in arrears and a constant rate for the entire term. Figures exclude fees, daily interest differences, rate changes and early repayment charges. Overpayments are assumed to shorten the term while retaining the original standard payment; your lender may treat them differently. This is not mortgage advice, an affordability decision or an offer.
Check your lender's overpayment rules first
Your mortgage may limit how much can be overpaid without an early repayment charge. The allowance, calculation period and treatment of a lump sum are contractual details, not a universal percentage.
Some lenders reduce the monthly payment after an overpayment; others may allow a term reduction. Ask how to request the intended treatment. This illustration does not assume your lender has agreed to it and excludes any charge.
How the illustration treats your payments
The one-off amount is applied to the balance at the start. Monthly overpayments are added to the original scheduled payment at each month end. Interest is calculated on the remaining balance at a constant rate, and the last payment is limited to the amount still owed.
No cashback is subtracted from the loan or assumed to be overpaid automatically. If you choose to overpay money received as cashback, it is still subject to your lender's allowance and rules.
Interest reduction is not the only consideration
Overpaying reduces access to cash unless the mortgage specifically allows it to be borrowed back. Consider an emergency buffer, more expensive debts and any alternative use of savings, with appropriate advice where needed.
Future rate changes, fees and early repayment charges can change the outcome. Compare the illustration with a remortgage decision rather than assuming every overpayment or switch produces the same benefit.
Sources and further reading
General mortgage information, not a personal recommendation. Lender criteria and scheme rules can change. Ask an adviser about your circumstances and a solicitor or tax adviser about legal or tax questions. Your home may be repossessed if you do not keep up repayments on your mortgage. Most buy-to-let mortgages are not regulated by the FCA.
Discuss the next step for your mortgage
Understand your options before you make a decision.