The best time to remortgage is just before your current deal ends. Start looking about six months out, as many lenders let you lock in a new rate that far ahead, and aim to have the new deal start the day the old one finishes. That way you never slip onto your lender's standard variable rate, which is usually far more expensive.
What happens when your deal ends
Fixed-rate and tracker deals normally last two, three or five years. When the deal ends, your mortgage doesn't stop. It moves automatically onto the lender's standard variable rate (SVR), which the lender sets and can change whenever it likes. SVRs are typically well above the rates on new deals, so your monthly payment can jump sharply the month after your fix ends.
Worked example: the cost of sitting on the SVR
Say you owe £200,000 with 20 years left. Your fix is ending and you're comparing an example SVR of 7.5% with a new fixed deal at an example rate of 4.5%. These rates are for illustration only.
| Example SVR 7.5% | Example new fix 4.5% | |
|---|---|---|
| Monthly payment | £1,611.19 | £1,265.30 |
| Difference per month | £345.89 | |
| Difference per year | £4,151 | |
| Interest paid over two years | £29,347 | £17,452 |
Even three months on the SVR in this example costs about £1,500 more in interest than being on the new rate. That's money spent for nothing, purely because the paperwork wasn't sorted in time.
Product transfer or full remortgage?
You have two routes when a deal ends.
A product transfer means taking a new deal from your existing lender. It's usually quick, often done online in minutes, and there's typically no new valuation, no legal work and often no full affordability check. The downside is you only see one lender's rates.
A remortgage means moving to a different lender. You get the whole market to choose from, which may mean a better rate, but it takes longer (often several weeks) and involves a valuation, legal work and a full affordability check. Many remortgage deals come with free valuation and free legal work to make switching easier.
A sensible approach is to get a product transfer offer from your lender and compare it with what's available elsewhere, ideally through a broker who can see most of the market. If your lender's offer is competitive, take the easy route.
A product transfer can also help if your circumstances have changed. If your income has dropped or you've become self-employed recently, passing a new lender's affordability check may be harder, while your existing lender may not need one.
Book your rate early
Many lenders let you secure a new deal around three to six months before your current one ends. If rates rise in the meantime, you keep the rate you booked. If rates fall, you can often switch to a cheaper deal before completion, though check whether there's a fee for changing. With a product transfer, some lenders open the window a bit later, so ask yours when you can apply.
Don't just look at the rate
Lenders often offer a low rate with a big arrangement fee, and a slightly higher rate with no fee. Which is cheaper depends on how much you're borrowing.
On a £200,000 balance over 20 years, compare an example deal at 4.2% with a £999 fee against one at 4.6% with no fee. Over two years the lower rate saves about £1,574 in interest, so even after paying the fee you're around £575 better off. Do the same sum on a £100,000 balance and the lower rate only saves about £787 in interest, so the fee-free deal works out about £212 cheaper.
The rule of thumb: on larger loans, low-rate deals with fees often win. On smaller loans, look hard at fee-free deals. Also watch for fees being added to the loan, because you'll then pay interest on them for years.
When remortgaging early makes sense
Leaving a deal before it ends usually means an early repayment charge (ERC), often a percentage of the balance that falls each year. On £200,000, even 2% is £4,000. It's rarely worth paying unless rates have fallen a long way, or you need to borrow more and your current lender won't help. Your mortgage offer shows the exact charges and the date they stop.
Other reasons to review your mortgage
- Your loan-to-value has improved. If you've paid down the balance or your home has gone up in value, you may now fall into a cheaper LTV band.
- You want to change the term. Shortening it raises payments but cuts total interest. Extending it does the opposite.
- You want to overpay. Some deals allow more flexible overpayments than others.
Put your own numbers into the remortgage calculator to see what switching would save.
This is general information, not financial advice.
Last reviewed October 2026.