The numbers to check before your mortgage deal ends

Mortgage renewal letters have a way of landing at the worst possible moment — and the instinct for most of us is to file them under "later" and hope the number isn't too bad when we finally open the statement.

It's worth twenty minutes now, though. Here's exactly what to check, what your options actually cost once you factor in the fees nobody mentions upfront, and when to start.

How much you actually owe, and what your home is worth now

The first two numbers to find are your outstanding balance and your property's current value, because together they set your loan to value, the biggest factor in the rate you will be offered next.

Your balance is on your last annual statement or your lender's portal. Your home's value is harder to pin down, but a free estimate from Zoopla or Rightmove, or a quick agent appraisal, gets you close enough. Do not assume your equity has grown as much as it might have a few years ago. According to the Halifax House Price Index for March 2026, the average UK home rose in value by just 0.8% over the year. Divide the balance by the value, and you will know roughly which pricing tier you are shopping in.

What actually happens if you let the deal lapse

Do nothing, and you move onto your lender's standard variable rate the day your deal ends, typically far higher than anything you were paying before.

The average SVR across the UK market was 7.13% in spring 2026, according to HomeOwners Alliance, against an average five year fixed rate of 5.44% at 75% loan-to-value, reported by Uswitch in August 2026. On a £250,000 balance with 25 years left, that gap is roughly £260 more a month, or just over £3,100 a year. That is the real cost of doing nothing, not a worst case.

The 3 routes, and the fees that quietly change the maths

You have three choices: transfer to a new product with your existing lender, remortgage with a new lender, or sit on the SVR, and the right one depends on fees as much as the headline rate.

A product transfer is usually quickest and skips the affordability checks a full remortgage requires, though it will not always find the sharpest rate. A new lender remortgage can be more competitive but often carries a booking or arrangement fee. The number most people forget is the early repayment charge, typically 1% to 5% of your balance according to HomeOwners Alliance, which on £250,000 could mean £2,500 to £12,500. Add arrangement fees of £500 to £2,000 or more, and switching early can still pay off, provided you compare pounds against pounds, not rate against rate.

When to start, and what to have ready

Most brokers suggest starting around six months before your deal ends, since offers stay valid for three to six months and several lenders let you reserve a rate well ahead of your renewal date.

Have your last three months of payslips, or two years of accounts if self-employed, plus recent bank statements and proof of ID and address. Lenders assess your current income, not what you earned when you first took the mortgage out, so check your affordability early if your circumstances have changed.

From Lucy, co-founder of Welleness

Our fixed rate came up for renewal last year, and I remember opening the letter from our lender and feeling a familiar sinking feeling, the one where you know you are about to lose an evening to spreadsheets and calls nobody else in the house wants to make.

What helped was doing the boring numbers first, the balance, the value, the loan-to-value, before I let myself get anxious about rates or headlines about the base rate. Once I had the real figures, the decision felt like something I could work through, one line at a time.

I think a lot of us carry this one quietly. It is rarely a crisis, it is just another thing that lands on whoever already tracks everything else. You do not need to become a mortgage expert. You need the right numbers and twenty minutes before you call anyone.

What you can do now

Find your mortgage end date and outstanding balance in your banking app or latest statement, and set a reminder for six months before that date.

Get a free instant valuation from Zoopla or Rightmove this week so you can work out your loan to value.

Call your existing lender for a product transfer quote, even if you plan to shop around too, so you have a real figure to compare against.

Frequently asked questions

What happens if my mortgage deal ends and I do nothing?

You move onto your lender's standard variable rate, which averaged 7.13% across the UK market in spring 2026, well above typical fixed rates.

Can I lock in a new rate before my current deal ends?

Yes. Most lenders let you reserve a rate three to six months ahead, so there is little reason to wait.

Will I pay a penalty for leaving my mortgage deal early?

Usually. Switching before your deal's official end date typically means an early repayment charge of 1% to 5% of your outstanding balance, according to HomeOwners Alliance.

Here is what one Welleness member said after completing her financial health check.

"The app triggered the realisation that speaking to one person who can look at everything is more valuable, rather than individual specialists who you then have to re-educate on all your different bits." Agnes, Welleness user

If working through these numbers has made you wonder what else could do with the same clarity, our free financial health check at insights.welleness.ai takes less than five minutes and gives you a clear picture across six areas of your financial life. No judgement, no jargon, just clarity.

This post is for informational purposes only and does not constitute financial advice. For guidance specific to your situation, speak to a regulated financial adviser.