Product transfer or remortgage: how to compare staying and switching

When a mortgage deal is ending, staying with the same lender is not the same process as replacing the loan with another lender. The cheapest-looking interest rate may not produce the lowest cost once product fees, legal work, valuation, incentives and the length of the deal are included.

Understand the two routes

A product transfer moves the existing mortgage onto another product with the same lender. A remortgage replaces it with a mortgage from a different lender. Extra borrowing, changing the borrowers or changing repayment type can turn either route into a more involved application.

Ask the current lender for every product available to you and the date from which a switch can take effect. Then gather comparable alternatives from the wider market. Do not cancel or accept anything until the effect on the existing deal and early repayment charge is clear.

Start with the expected balance

Use the Mortgage Balance at Renewal calculator to estimate the balance on the planned switch date. A comparison based on today’s balance can be misleading if several normal repayments are still due. Confirm the final figure with a redemption statement before completion.

Estimate current loan-to-value with a cautious property value. A new lender will make its own valuation, and the current lender may also use an automated or updated value. Compare what happens if the formal value is lower than expected.

Compare cost over the same period

Choose a consistent comparison period, such as the initial fixed period. Record the interest rate, payment, product fee, valuation and legal costs, cashback and any cost of leaving the current mortgage. If a fee is added to the loan, include both the higher balance and the interest charged on it.

Run the same balance and term through the Mortgage Repayment calculator for each rate. The result is an estimate based on a constant rate, so use the lender’s illustration for contractual payments and total-cost figures.

Allow for eligibility and affordability checks

The FCA says borrowers who are up to date and are not borrowing more will often be able to switch deal with their existing lender without another affordability check, although this is not guaranteed. Moving to a new lender will normally involve an application, affordability assessment, credit checks and a valuation.

A simpler process can be valuable when income or circumstances have changed, but it does not prove the current lender’s deal is cheapest. Equally, an attractive market rate is not useful if the product is unavailable for the required LTV, property type, income or loan size.

Check fees, penalties and incentives

List every cash cost and when it is payable. Free legal work or a free valuation may have conditions, while cashback might arrive after completion. Check whether a product fee is refundable if the application fails. Confirm any early repayment charge on both the old deal and the new product.

Overpayment allowances, portability and the follow-on rate also matter. Do not rely on a common overpayment percentage: read the particular mortgage conditions and ask how an overpayment would affect the term or monthly payment.

Think about future plans

A longer fixed period may offer payment certainty but can be costly if you expect to move, repay a large amount or change the borrowers. Portability still requires approval for the new property and circumstances. If selling is realistic, compare the flexibility and potential early repayment charge as carefully as the initial rate.

Make a decision sheet

• Use the same balance, term and comparison period for each option.
• Show fees both upfront and added to the loan.
• Record valuation, legal and cashback assumptions.
• Check application requirements and the offer expiry date.
• Note early repayment, overpayment and portability terms.
• Keep the lender’s illustration with the final comparison.

Limits and official guidance

This guide does not recommend a mortgage or assess eligibility. MoneyHelper explains the costs and choices involved in remortgaging, and the FCA outlines switching and support options. If a house move affects the choice, use the GOV.UK guidance on preparing to sell. A regulated mortgage adviser can make a recommendation based on your full circumstances.

If an apparently cheaper deal comes with fees, check how long the monthly difference takes to repay them in mortgage switching break-even guide.