Remortgage
Calculator

Start by entering your current mortgage details: the remaining balance, the interest rate you are paying and how many years you have left on your term. These figures determine your existing monthly repayment and the total interest you will pay if you stay on your current deal.

Next, enter the terms for your proposed new mortgage. Set the new interest rate your lender or broker has quoted, choose a new term length and enter any arrangement fees. Arrangement fees typically range from nothing on fee-free deals up to around £2,000 for the most competitive rates.

The calculator uses a standard amortisation formula to compute both your current monthly repayment and the new monthly repayment. It then subtracts the new figure from the old one to show your monthly savings. The break-even point tells you how many months of savings it takes to recoup the arrangement fees you paid upfront.

Finally, it calculates total interest paid under both scenarios and subtracts arrangement fees from the interest saved to give you a true net savings figure. If the net savings is positive and the break-even period is shorter than the time you plan to stay on the new deal, remortgaging is likely a sound financial decision.

When your fixed rate ends. Most UK homeowners are on a fixed-rate deal lasting two to five years. When the deal period ends, your lender moves you onto their standard variable rate (SVR), which is typically 1 to 3 percentage points higher. Remortgaging before your deal expires avoids the SVR altogether and can save you hundreds of pounds per month.

Early repayment charges (ERCs). If you leave your current deal before it ends, your lender may charge an ERC — usually between 1% and 5% of the outstanding balance. On a £200,000 mortgage, that could be £2,000 to £10,000. Always check whether the savings from a lower rate outweigh the ERC before switching early.

Arrangement fees vs fee-free deals. Lenders offer two main pricing models. A fee-paying deal charges an upfront arrangement fee (typically £500 to £2,000) in exchange for a lower interest rate. A fee-free deal has no upfront cost but a slightly higher rate. For smaller mortgages the fee-free option often works out cheaper overall, while larger mortgages benefit more from paying the fee for a lower rate.

Product transfer vs full remortgage. A product transfer means switching to a new deal with your existing lender. It is faster, requires less paperwork and usually involves no valuation or legal fees. A full remortgage means moving to a different lender, which may offer better rates but involves a fresh application, affordability assessment, valuation and conveyancing. Compare both routes before deciding.

Loan-to-value (LTV) matters. Your LTV ratio — the mortgage balance as a percentage of your property value — directly affects the rates available to you. The best rates are reserved for borrowers at 60% LTV or below, with further thresholds at 75%, 80% and 90%. If your property has increased in value since you bought it, your LTV may have improved enough to unlock a cheaper rate band.

Stamp duty does not apply. Unlike purchasing a property, remortgaging does not attract stamp duty land tax. This applies whether you do a product transfer with your existing lender or a full remortgage with a new one.