Remortgaging when your fix ends: how much reverting to SVR costs

What happens automatically when a fix ends

A fixed-rate or tracker deal has a defined end date written into the mortgage offer. If nothing is done before that date, the mortgage doesn't stop or get called in – it simply switches to the lender's Standard Variable Rate (SVR) from the next payment. SVR is set by the lender at its own discretion, is almost always the highest rate that lender charges on its mortgage book, and applies with no further paperwork or approval needed on the borrower's side.

As of 2026, the average SVR across UK lenders sits around 7.15%, though individual lenders vary considerably – some sit near 6.3%, others above 8%. Whatever a specific lender's SVR is, it's set independently of the fixed or tracker rate that came before it, and is normally well above both.

Worked example: five years into a 30-year mortgage

Take a £280,000 mortgage over 30 years, on a 5-year fix at 4.2%. The monthly payment during the fix is £1,369.25, and after 5 years of payments the outstanding balance is £254,061.98, with 25 years left on the original term.

Doing nothing costs £393.42 a month more than remortgaging onto a representative new 5-year fix – £4,721.04 over a year. That gap is the entire reason remortgaging exists as a routine step rather than an occasional one: it isn't about chasing a marginally better rate, it's about avoiding the lender's most expensive rate by default.

Remortgage vs. product transfer

There are two distinct routes to a new rate, and they're not the same process. A product transfer stays with the existing lender and moves onto one of its current deals – usually a quick process, often without a new affordability assessment or credit check, because the lender already has the loan on its books. A remortgage moves the loan to a different lender entirely, which requires a fresh application, income verification, and usually a credit check and property valuation, in exchange for potential access to a better rate elsewhere.

• A product transfer is typically faster and has a lower bar to clear – useful if income, credit history or the property itself has changed in a way that might complicate a new lender's checks.
• A remortgage to a different lender can be worth the extra process if that lender's rate is meaningfully lower, but it also brings solicitor and valuation costs that a product transfer usually avoids.
• Some borrowers use a mortgage broker to compare both routes at once – the broker searches product transfer rates from the existing lender alongside remortgage rates from others.

When to start the process

Most UK lenders allow a new rate to be booked 3 to 6 months before the current deal's end date, and in most cases that booking can be swapped for a better rate right up until completion if one becomes available in the meantime. There's essentially no downside to booking early other than the (usually free) time spent doing it – the main risk is booking too late and having no new deal ready when the old one expires.

What changes besides the rate

A new deal can also mean a new term – shortening the remaining term increases the monthly payment but reduces total interest, while extending it does the reverse. It's also a natural point to reconsider fixed versus tracker, review whether overpayments are affordable, or, for a remortgage to a new lender, borrow a bit more against increased equity if that's needed for other purposes. None of these decisions are forced by the process, but the remortgage point is when they're cheapest to make, since most other times carry an early repayment charge for making the same changes mid-deal.