Compare your current mortgage to a new remortgage deal and see your monthly savings and break-even point.
Rates as of Q2 2025 (example)
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A remortgage calculator compares your current mortgage payment to a new mortgage deal — typically taken out when your existing fixed-rate or other introductory deal is ending — and shows your potential monthly savings, the total interest on each loan, and how long it would take for those savings to cover the fees of remortgaging (your "break-even point").
The calculator computes the monthly payment for your current mortgage (based on your current balance, rate, and remaining term) and compares it to the monthly payment for the new mortgage (based on the same balance, the new rate, and new term). The difference is your monthly savings, and dividing the remortgage fees by your monthly savings gives the break-even point in months.
Formula: Monthly Payment = [Balance × r × (1+r)n] / [(1+r)n − 1] for each loan, using its own rate and term. Monthly Savings = Current Payment − New Payment. Break-Even (months) = Remortgage Fees ÷ Monthly Savings.
Example: For a £200,000 balance, moving from a 6% rate with 22 years remaining to a new 5% rate over a 25-year term, the current payment is roughly £1,366/month and the new payment is roughly £1,169/month — a monthly saving of about £197. With £1,000 in remortgage fees, the break-even point is about 6 months (£1,000 ÷ £197 ≈ 5.1, rounded up). (Note: all figures in this example are for illustration purposes only and do not represent a mortgage offer.)
Most UK mortgage holders remortgage when their initial fixed-rate (or other introductory) deal ends, to avoid moving onto their current lender's standard variable rate (SVR), which is usually higher. Remortgaging can mean switching to a new deal with your existing lender (sometimes called a "product transfer," which may involve lower or no fees) or moving to a new lender entirely (which typically involves a fuller application and remortgage fees like the ones in this calculator). If you're remortgaging before your current deal ends, check whether your existing mortgage has an early repayment charge (ERC) — this is a separate cost not included in this calculator and could significantly affect whether remortgaging early makes financial sense. Extending your mortgage term when remortgaging (for example, resetting back to 25 years even if you had fewer years left) can reduce your monthly payment but may increase the total interest paid over the life of the loan — this calculator's "total interest" figures help illustrate that trade-off.
Most fixed-rate (or other introductory) mortgage deals last a set number of years, after which you typically move to your lender's standard variable rate (SVR), which is usually higher. Remortgaging — either with a new lender or via a product transfer with your existing lender — lets you secure a new competitive rate instead of paying the SVR.
The break-even point is how many months it takes for your monthly savings from a lower rate to cover the fees of remortgaging (arrangement, legal, and valuation fees). If you plan to move or pay off your mortgage before reaching the break-even point, remortgaging might not be worthwhile despite the lower rate.
No. If you're remortgaging before your current deal ends, your existing lender may charge an early repayment charge (ERC), often a percentage of the outstanding balance. This is a separate cost not included in this calculator and should be checked with your current lender before remortgaging early.
A product transfer is when you switch to a new deal with your existing lender, rather than moving to a new lender entirely. Product transfers can sometimes involve lower fees and a simpler process than a full remortgage with a new lender, though it's still worth comparing rates across the market.
If you extend your mortgage term when remortgaging (for example, resetting to a longer term than you had remaining), your monthly payment decreases because it's spread over more months — but the total interest paid over the longer term can end up higher, even at a lower interest rate, depending on the rates and terms involved.
Many UK lenders allow you to secure a new mortgage offer several months before your current deal ends, often three to six months in advance, which can be set up to take effect right when your current deal expires — helping you avoid moving onto the lender's standard variable rate even temporarily.
Disclaimer: The information, rates, and figures provided on this page are for educational and illustrative purposes only and do not constitute a mortgage offer or financial advice. The default interest rates are sample values and do not reflect rates currently available from any specific lender. Remortgage fees, early repayment charges, and mortgage terms vary by lender and depend on your individual circumstances. Always obtain a personalised quote from a mortgage lender or broker and consult a qualified financial adviser before making any remortgaging decisions.