Part exchange on a house in the UK: what it really costs you

Part exchange gets you out of your old house fast, and it costs you a lot. Zoopla's 2024 guide puts the builder's price at 80% to 90% of what your home would fetch on the open market. On a £300,000 house that is £30,000 to £60,000 gone. You save the agent fee, which is about £4,260 on that price, and you skip two or three months of bills. So the speed costs you seven to fourteen times the fee you avoid.

For most sellers that is a bad trade. It is a good one in three cases: your buyer has just pulled out, you cannot carry two homes, or the plot you want will go to someone else if you wait.

The builder is not doing you a favour. There is a stamp duty relief written for house builders that takes your old home out of tax on their side, and it is the reason the offer exists at all. That is the strongest card you hold when you talk about price.

What the deal actually is

• What you get: 80% to 90% of open market value, per Zoopla's 2024 guide.
• What you save: the agent fee, the marketing, and the risk of a chain falling over.
• Who qualifies: your home must be worth 70% or less of the new one at Taylor Wimpey, or 80% or less and no more than £500,000 at Barratt.
• What sets the price: two valuations and an assumed sale in 8 to 10 weeks, on Barratt's published terms.
• What it does to your tax: nothing, if the house has always been your only home. Read the last two sections if it has not.
• The better first ask: assisted move, where the builder pays the agent and you keep the open market price.

What is part exchange, and which builders offer it?

Part exchange means the builder buys your old home and knocks the price off your new one. Two deals, tied together, both done on the same day. There is no chain, no viewings and no agent, and you move once.

Most of the big national house builders run a scheme, and the terms sit on their own websites. Barratt publishes one. Taylor Wimpey publishes one and runs a second scheme called easyMover beside it. Smaller builders often offer it too, but usually only on plots they want to move, so ask rather than assume.

The link between the two deals is not just marketing. It is a condition of the tax relief the builder is claiming, and it is why they will not simply buy your house and let you shop elsewhere. If you walk away from the new plot, the offer on your old home goes with it.

How does the builder work out your valuation?

Not by guessing, and not by taking an agent's asking price. Barratt says it runs two independent evaluations of your home, and that its offer is based on the premise that the house will sell between 8 and 10 weeks. Taylor Wimpey says its opening offer in England and Wales is subject to the RICS survey and valuation, and that in Scotland it works from the Home Report value.

Read those two lines together and the discount stops being a mystery. You are not being offered market value. You are being offered the price a surveyor thinks your house would fetch if it had to sell inside ten weeks. That is a lower number, and it is a real one.

No builder publishes the size of its own discount. The one published figure comes from Zoopla's guide of 16 September 2024, which says a developer might get your old home for 80% to 90% of the price it might have achieved on the open market. Treat that as press commentary, not a builder's promise. Your own gap turns on your house, your area, and how fast that surveyor thinks it would move.

Is part exchange worth it? The numbers on a £300,000 home

Here is the comparison in full. The property value is a stated example and the figures are illustrative.

Item	Part exchange	Open market sale
Price you get for the house	£240,000 to £270,000	£300,000
Estate agent commission	Nil	About £4,260
Photos, listing and energy certificate	Nil	Paid by you
Legal work on the sale	Paid by you	Paid by you
Bills and mortgage while it sits on the market	Nil	Two to three months of your own running costs
Removals	Paid by you	Paid by you
What you keep, before legal fees and removals	£240,000 to £270,000	About £295,740, less a few months of bills

The agent figure comes from the HomeOwners Alliance, whose 2026 guide puts the average sole agency high street fee at 1.42% including VAT. On a £300,000 sale that is £4,260. Our guide to what estate agents charge to sell a house breaks the range down, and the cost of moving house covers the rest of the bill.

So you hand over £30,000 to £60,000 to save £4,260 and a few months of running costs. That is the whole trade, and it is why part exchange suits so few people. It suits you when the date is worth more than the money: your buyer has just pulled out, your reservation runs out next month, or you are paying for two homes and cannot keep it up.

If it is only the chain risk that worries you, ask about assisted move before you accept, and price the open market route properly first. Our cost of selling a property guide sets out the full bill. If speed is what you are really buying, the other quick routes trade price for certainty in much the same way, and the modern method of auction is the closest comparison.

Do you qualify? The conditions each builder publishes

There is no industry rule here. Each builder sets its own bar, publishes it, and the bars are different.

• Taylor Wimpey: your existing home must be 70% or less than the value of the new home you are considering purchasing. On a £300,000 home, that means a new plot of at least £428,571.
• Barratt: your current home should not be more than 80% of the price of the home you want to buy, and the scheme runs to properties up to a maximum value of £500,000. On a £300,000 home, that means a new plot of at least £375,000.

Taylor Wimpey also rules some homes out. Its terms say leasehold properties with less than 85 years remaining on the lease, or ones that include any commercially onerous terms, cannot be considered, and that homes unsuitable because of their method of construction or unusual characteristics are out as well. Check your lease length first.

Then there are the conditions that make the builder's tax relief work, and those bite on you too. You must have lived in the old home as your only or main home at some point in the two years up to the sale. You must mean to live in the new one as your only or main home. The two purchases must be entered into in return for each other. And the land cannot exceed the permitted area, which starts at half a hectare of garden and grounds including the ground the house stands on. Miss one and the builder loses the relief, which usually means the offer goes.

Can you negotiate the offer, and what moves it?

Yes, but evidence moves it and asking does not. Four things work.

• Get three written agent valuations before their surveyors visit. Ask each agent for a realistic ten week figure as well as an asking price. The ten week number is the one you argue with, because it is the number the builder is using.
• Ask which two firms valued you, and what sale period they assumed. If the offer is built on an eight week sale and your street runs slower than that, say so and ask for it to be re-run at twelve.
• Ask for the gap in extras rather than in price. Builders protect the headline price on the new home because it sets the value of the rest of the phase. Flooring, turf, a kitchen upgrade or your legal fees are far easier for them to give away.
• Say out loud that they pay no stamp duty on your house. Most sellers have no idea, and it changes the tone of the conversation.

The fifth lever is the strongest and it is not a line, it is a fallback. Be ready to walk to assisted move. Nothing moves a part exchange figure like a seller who has a second route and does not need this one.

Part exchange, assisted move or chain break: which are you being offered?

These three get used as though they mean the same thing. They do not, and the tax rules treat them as three separate arrangements with three separate sets of conditions.

• Part exchange. The builder buys your old home itself. Guaranteed sale, guaranteed date, biggest discount.
• Assisted move. Your home goes on the open market with an agent and the builder pays the agent. Taylor Wimpey's terms say that if the complete transaction proceeds to mutual legal completion, any fees and commissions for the appointed agents will be met by Taylor Wimpey. You keep the open market price. You do not get a guaranteed sale.
• Chain break. Your buyer has already collapsed. A property trader steps in and buys your old home so that your purchase survives.

Read the exit clause on an assisted move before you sign. Taylor Wimpey's terms say that if either side withdraws and you then sell to a buyer the agent introduced, you will be responsible for the agents' fees and commission plus VAT. That is a fair term and it is easy to miss.

Take assisted move first if you can live with the uncertainty, because it is the only one of the three where you keep the full market price. Part exchange is what you take when the date matters more than the money.

Who pays the stamp duty on your old house?

You do not. Nobody pays stamp duty for selling a house. The buyer pays it, and here the buyer is the builder.

Except the builder does not pay it either. There is a relief for house building companies that takes their purchase of your old home out of stamp duty altogether, as long as the deal meets the conditions in the section above. That relief is why part exchange works as a product. Without it, the builder would be paying tax on every home it took in.

Be clear whose relief it is. It is theirs, not yours. You would have paid no stamp duty on selling your house in any event, so nobody is passing you a saving. Anyone who presents it to you as a benefit is selling you something. Treat it as a fact about their margin and use it.

You do pay stamp duty on the new home. HMRC's stamp duty manual treats an exchange of homes as two purchases and charges each one on the value of what is acquired, so your bill is worked out on the full price of the new home, not on the cash you hand over on top. Run your figure through the stamp duty calculator before you reserve, and check whether the extra rate for a second home applies to you. If you are curious why the builder charges no VAT on the new house either, VAT on new builds covers the other side of the deal.

Do you pay capital gains tax on a part exchange?

Usually not. Part exchange is a sale for tax, and the fact that the money arrives as credit against a new house changes nothing. If the old home has been your only or main home for the whole time you owned it, private residence relief covers the gain and there is nothing to pay and nothing to report.

Three cases break that. You let the house out for part of the time you owned it. It was a second home or a holiday place. Or the garden and grounds are bigger than the relief reaches. The starting point there is half a hectare, including the ground the house stands on. A larger area counts only where it is genuinely needed to enjoy the house as a home, judged against the size and character of the house itself. Anything past that sits outside the relief. This is not word for word the same test as the builder's stamp duty one. That test has the same half hectare starting point, but it does not tie the larger area to enjoying the place as a residence. A big garden can pass one and fail the other. In all three cases the gain is taxable, and part exchange makes it worse for one reason: the costs of selling come off the gain, and this route strips most of them out. No agent fee to deduct, because there was no agent. No marketing spend, because there was no marketing. Removal costs never came off the gain in the first place, and nor does mortgage interest.

The discount does at least count for something. The builder is not connected to you, so the tax is worked out on the price you actually agreed, low as it is. Take £255,000 for a let property worth £300,000 and the £45,000 you gave up cuts the taxable gain by £45,000, worth £10,800 back at the 24% rate. You still gave up £45,000 to get £10,800 back, and if private residence relief covers you, you get none of it back at all.

That is as far as this page goes on tax, because the mechanics are a subject of their own. If your old home was let or was a second property, our complete guide to capital gains tax on property has the rates, the reliefs and the deadline.

What happens if the new build is not what was promised?

Less than you would expect. Parliament passed a law in 2022 that would have set up a statutory ombudsman for new build buyers. It has never been brought into force and no date has been set. So there is no statutory right of redress for a bad new build.

What exists instead is voluntary. The New Homes Quality Board runs the New Homes Quality Code, now on version 2 of March 2026 for homes reserved from 2 March 2026, with version 1 of October 2023 covering earlier reservations. Buyers of builders that have registered can take a complaint to the New Homes Ombudsman Service. Builders that have not registered sit outside it, and registering is a choice they make rather than a duty they owe.

A second voluntary code, the Consumer Code for Home Builders, still runs alongside it, and the major warranty providers list it as the code their registered builders follow. Ask your builder which one they have signed and when, because the answer decides where a complaint goes. Ask before you reserve, not after.

None of this changes because you part exchanged. Your old home is gone either way, and that is the real risk of the route. You have nothing to go back to if the new one disappoints.

What to do next

You do not have to answer the builder today. Put your own figures into our cost of selling calculator, which prices an open market sale in under a minute and shows you what one would have left you. If the gap to the builder's offer is smaller than you feared, take the certainty. If it is not, go back and ask for assisted move instead.