Selling Your House During a Fixed-Rate Mortgage

Can you sell your house during a fixed-rate mortgage?

Yes. There is no legal or contractual rule that stops you selling a property while your fixed-rate deal still has time to run. What changes is how your existing mortgage is treated when the sale completes. You will either carry the existing rate across to your next property (porting), pay an early repayment charge to settle the mortgage in full, or — in some cases — qualify for a waiver that lets you out of the deal with no charge.

Lenders quote ERCs as a percentage of the outstanding balance, typically in a range of 1% to 5% depending on how long is left on the fix. On a £300,000 mortgage that's £3,000 to £15,000 — large enough to be worth understanding properly before you accept an offer on your home.

The three possible routes when you sell mid-fix

When the sale completes, your mortgage has to be settled. The route you take depends on what you're doing next:

The right route is almost never obvious from the outside — it depends on the gap between your current rate and today's market rates, the size of the ERC, and whether the new lender (if any) will offer you better terms. A 15-minute conversation usually settles it.

Option 1: Porting your mortgage to a new property

Porting is the cleanest answer when your current rate is meaningfully below current market rates, because it preserves the saving. You don't pay an ERC on the portion you carry across, the existing rate and end date stay intact, and any additional borrowing for the new property sits on a separate part of the mortgage at a current market rate. We covered the mechanics in detail in porting your mortgage and borrowing more.

Two things to know before you assume porting will work:

• Porting is not automatic. The lender re-runs affordability in full on the larger combined balance, using today's stress-tested rates. Affordability rules have tightened in 2025–26, which is why we've seen clients who comfortably passed three years ago decline on the new application even though their lender "allows" porting.
• The window matters. Most major lenders give you somewhere between 90 days and 6 months between sale completion and purchase completion. Lender-by-lender windows are in the table further down.

If porting works, it's usually the best financial outcome. If affordability or LTV blocks it, the other two routes come into play.

Option 2: Paying the early repayment charge — what it actually costs

The headline ERC is a percentage of the outstanding balance — most commonly 1% to 5%, tapering down as you get closer to the end of the fix. So a 5-year fix that started recently might carry a 5% ERC in year one, falling by roughly a percentage point each year. Your exact figure is in your mortgage offer document and on your annual statement — not something a lender's marketing site publishes.

Two reliefs usually apply alongside the headline ERC:

• The annual overpayment allowance. Most lenders let you repay up to 10% of the outstanding balance each year (a few allow higher amounts on fixed and tracker products) without triggering an ERC. When you sell, the unused allowance for the current year is subtracted from the redemption amount before the ERC is calculated — so your effective ERC is often a touch lower than the headline rate.
• Daily reduction. Some lenders calculate the ERC as a percentage per remaining year of the fix on a daily basis. That means selling on the 1st of the month versus the 30th can shave hundreds of pounds off the bill.

Paying the ERC can still be the right call. If today's market rates are lower than your existing rate, the cheaper monthly payments on a new product can recoup the ERC inside a couple of years.

Option 3: Selling without buying again — when ERCs are unavoidable

Some sales don't have a new property attached. Downsizers moving into rented or family accommodation, divorcing couples selling the family home and splitting the proceeds, executors settling an estate, and homeowners moving abroad all fall in this category.

In these cases there is no porting option. The mortgage gets settled in full on completion, and the ERC comes out of the sale proceeds before you see them. The questions worth asking your lender are narrow but worth thousands:

• Does the annual overpayment allowance apply to the redemption? (It usually does.)
• Is there a hardship or critical-illness waiver in your circumstances? Several lenders will waive ERCs for borrowers diagnosed with a critical or terminal illness, or in genuinely involuntary financial hardship.
• If you are within a few months of your fix ending, would the lender accept the redemption inside an ERC-free window?

These conversations are easier when a broker has them on your behalf, because we know which arguments each lender's retentions team actually entertains.

What to expect on the ERC — structure and reliefs

UK lenders don't publish year-by-year ERC percentages on their public sites — your exact figure is in your mortgage offer. What they do publish is the structure: how the ERC tapers, the overpayment allowance, whether porting is available, and the porting window. Those four variables decide which route makes sense.

Structures verified June 2026 from major UK lender customer policy pages. Specifics vary by product and time elapsed — check your mortgage offer for your exact percentages, or contact our team for the precise position on your case.

Lender variations you should know about

The structural picture is consistent across the market, but the details vary lender by lender — and those details are where the saving (or the penalty) sits. Five variations to confirm on your specific product before you commit:

1. The porting window is your single most important date

Windows range from about 90 days from sale completion at the short end to 6 months between sale and purchase at the long end. The shorter your window, the tighter the chain has to be. If your sale and onward purchase aren't running on the same timetable, the window is what dictates whether porting stays viable. Find out yours before you exchange.

2. Some longer fixes use a flat ERC instead of tapering

On most products the ERC drops a percentage point or so per year, so waiting helps. On some 5- and 10-year products the ERC is flat for the whole term, so waiting doesn't. That changes the cost-of-delay calculation completely — and it's a detail buried in your mortgage offer. Worth checking.

3. Daily reduction can shave hundreds off the bill

Several lenders calculate the ERC reducing on a daily basis through the remaining years of the fix, rather than charging the full annual rate until the next anniversary. Where that applies, the difference between completing on the 1st of the month versus the 30th can be hundreds of pounds — sometimes more on a large balance.

4. Overpayment allowances aren't all 10%

The market norm is 10% of the outstanding balance per year. A few lenders allow up to 20% per sub-account on fixed and tracker products, which can be useful for chipping the balance down ahead of sale — reducing the figure the ERC percentage is applied to.

5. Home-mover waivers exist, but you have to ask

A handful of lenders waive the ERC for existing customers moving home if they're within 6 to 9 months of their fix ending. Critical-illness and hardship waivers are more widely available. None are automatic — they go through the lender's retentions or hardship team with supporting evidence. We'll handle the application if your circumstances qualify.

6. Additional borrowing rules differ if you're porting + topping up

If you need to borrow more on the new property alongside the port, the rules vary: minimum top-up amounts, whether the additional borrowing is priced on a current rate or parked on the standard variable rate, and the maximum LTV that applies including the top-up. We covered the lender-by-lender picture in our companion piece on porting your mortgage and borrowing more.

What if my buyer has already had an offer accepted?

This is where the panic usually starts — the buyer is ready, the chain is forming, and someone has just mentioned ERCs. A few practical points:

• You have more time than you think. Most sales in a chain take 12–16 weeks from offer to completion. Inside that window we can compare the port vs ERC option in detail, get a decision in principle from your existing lender, and run the alternative through other lenders on our panel.
• Don't sign the contract until you've checked your mortgage offer. Your offer document spells out the ERC schedule and the porting deadline. Knowing both before you exchange contracts can save thousands.
• Tell us early if completion is tight. A 90-day porting window is comfortable in a normal chain. It becomes pressured if your sale and onward purchase are running on different timetables. Coordinating the dates is part of the job.

Can you avoid the early repayment charge entirely?

There are four legitimate scenarios where the ERC disappears or shrinks materially:

1. Wait until the fix ends. If you're within a few weeks of the end of your fixed deal, holding your sale until the ERC-free window starts is the cleanest answer. Lenders typically allow a switch-to-new-deal or full redemption inside the final few months without ERC.
2. Port successfully and complete inside the window. No ERC on the ported portion.
3. Trigger a lender waiver. Critical illness, terminal diagnosis, bereavement, and (with some lenders) home moves within 6 to 9 months of fix end can all qualify. These are not automatic — you have to apply, with evidence, through the lender's retentions or hardship team.
4. Use the overpayment allowance to shrink the balance. It doesn't avoid the ERC, but it does reduce the figure the percentage is applied to. On a £400,000 balance, using the full 10% allowance shaves £4,000 off the redemption before the ERC is calculated — that's £200 off a 5% ERC.

What our team actually does for clients in this position

When a client comes to us mid-fix and ready to sell, the work usually breaks down as follows:

• Cost comparison in writing. Port the existing mortgage versus pay the ERC and remortgage to a new lender — we model both, including ERC, monthly payments, fees, and any additional borrowing, and put the numbers side by side.
• Direct conversations with the lender's case team. When porting affordability is borderline, the difference between a polite "no" and a "yes with conditions" is often whether the case is presented properly. We've placed enough cases with each major lender to know which evidence each one cares about.
• Timing the application around your sale. Sale completion, purchase completion, and porting application have to line up inside the lender's window. Co-ordinating those dates — including liaising with your solicitor — is part of how we keep cases on track.
• Access to 90+ UK lenders if porting isn't viable. If the existing lender won't approve the larger combined balance, or the LTV ceiling blocks the port, a new mortgage on the new property is sometimes the better answer. We compare both sides honestly and recommend whichever costs less over the remaining fixed-rate period.

Last updated: 4 June 2026. Reviewed by Daniel Groves, Director, Bright Box Financial Services. The information in this article is general guidance, not personal financial advice — ERC structures and lender policies change frequently, so contact us for advice tailored to your circumstances. Your home may be repossessed if you do not keep up repayments on your mortgage.

Frequently asked questions

Can I sell my house during a fixed-rate mortgage?

Yes. There is no legal or contractual rule that stops you selling a property while your fixed-rate deal still has time to run. What changes is how your existing mortgage is treated when the sale completes — you’ll either port the rate across to your next property, pay an early repayment charge (typically 1% to 5% of the outstanding balance) to settle the mortgage in full, or qualify for a lender waiver. Which one depends on whether you’re buying again, your lender’s porting rules, and how much your ERC would be.

How much is the early repayment charge for selling a house?

The ERC is set out in your mortgage offer. As an industry range, ERCs sit between 1% and 5% of the outstanding balance, tapering down as the fix runs out. On a £300,000 mortgage that's £3,000 to £15,000. Your annual statement also shows the current figure. If you can't find either document, your lender will quote it on request.

Can I port a fixed-rate mortgage to a new property?

In most cases, yes. Most major UK lenders allow porting subject to a new affordability assessment and LTV check on the new property. Porting is not automatic — the lender treats it as a new application — and you must complete inside their porting window, typically 90 days to 6 months.

What happens to the money from the sale if I still have a mortgage?

When the sale completes, your solicitor uses the proceeds to repay your outstanding mortgage balance to the lender first. The ERC (if any) is deducted at the same time, alongside legal fees and estate agent fees. What's left is yours, and is usually transferred to your account or carried forward as deposit on your onward purchase.

Do all fixed-rate mortgages have early repayment charges?

Almost all do — it's the trade-off lenders ask for in exchange for the fixed rate. The exception is the period inside the fix when the ERC tapers to zero (typically the final few months before the deal ends) and any retention products the lender offers to keep you on. Tracker and standard variable rate products usually don't carry ERCs, but they don't give you the rate certainty of a fix either.

How long do I have to complete my new purchase if I'm porting?

It depends on your lender. Across the major UK lenders the porting window ranges from about 90 days from sale completion to 6 months between sale and purchase. Some lenders also operate an ERC-refund mechanism: you pay the ERC at redemption and the lender refunds it once the new mortgage completes inside the window. Miss the window and the port falls away — your old rate goes, and any ERC becomes payable.