Before You Take a Fixed Rate Mortgage: What Happens When It Ends

What a fixed rate mortgage fixes and what it does not

A fixed rate mortgage locks the interest rate charged on the outstanding balance for the agreed period. The monthly payment amount is therefore predictable for the duration of the fix. The rate does not change if the Bank of England base rate rises or falls during the fixed period. At the end of the fixed period, the rate automatically reverts to the lender's standard variable rate, which tracks or is influenced by the base rate and is set at the lender's discretion.

The risks most people do not check

The SVR reversion is the most costly trap in the mortgage market. SVRs in 2024 were typically six to eight percent, while competitive fixed rates were available at four to five percent. A borrower with a £200,000 mortgage who does not act at the end of their fix pays an additional £200 to £400 per month on the SVR. Across a year this is £2,400 to £4,800 in excess interest payments.

Longer fixes carry more interest rate risk. A five or ten year fix locks you in when rates may fall. If the Bank of England cuts the base rate significantly during a long fixed period, you cannot benefit without paying an ERC to exit early. Shorter fixes offer more flexibility but require more frequent remortgaging decisions.

The lowest headline rate is not always the cheapest deal. A rate of 3.99 percent with a £1,499 arrangement fee may cost more over the fixed period than 4.19 percent with no fee, depending on the loan size and term. Always calculate total cost of credit over the fixed period including fees.

New-build reservation periods can expire. Buyers of new-build properties often reserve a mortgage rate months before completion. If the completion is delayed, the rate offer may expire and need to be extended or replaced at current rates.

What to verify before fixing

Calculate total cost of credit over the fixed period for each product being compared: monthly payment multiplied by number of months in the fix, plus all fees. Compare the result, not just the headline rate. Set a calendar reminder six weeks before the fix end date to begin the next product search.

Where to complain

Unsuitable mortgage advice complaints go to the Financial Ombudsman Service after the firm's internal complaints process.

Frequently asked questions

What is the difference between a fixed rate and a tracker mortgage?

A fixed rate does not change during the fixed period regardless of base rate movements. A tracker mortgage follows the Bank of England base rate at a set margin above or below it, meaning payments change when the base rate changes.

Can I leave a fixed rate mortgage early?

Yes, but you will typically pay an early repayment charge of one to five percent of the outstanding balance. The ERC decreases as you approach the end of the fixed period and is waived entirely within the 49-day window before the deal ends.

What happens if I do nothing when my fix ends?

You automatically revert to the lender's SVR. This is almost always a significantly higher rate than available fixed products. You can remortgage or take a product transfer at any point, but acting proactively before the fix ends avoids a period on the SVR.

Is a longer fix always safer?

Not necessarily. A longer fix provides more payment certainty but reduces flexibility and can be costly to exit if rates fall. The appropriate fix length depends on your circumstances, how long you plan to stay in the property, and your view on future rate movements.

Are arrangement fees always worth paying for a lower rate?

This depends on the loan size and fix length. On larger loans over longer fix periods, a lower rate with a fee often wins on total cost. On smaller loans or shorter fixes, a fee-free product at a slightly higher rate can be cheaper overall. Always calculate total cost of credit.