Exchange and completion explained

Exchange of contracts is the moment a house sale in England or Wales becomes legally binding. The completion date is fixed and the buyer pays a deposit. Completion is the day the buyer's money arrives, ownership passes to them and you hand over the keys. GOV.UK says completion is often around 2 to 4 weeks after exchange, but the two can happen on the same day.

Until exchange, either side can walk away. After it, pulling out has serious consequences. This guide explains both stages from the seller's side, what you need to do in between, and what can still go wrong.

What is exchange of contracts?

A contract to sell a home in England or Wales has to be in writing, include all the agreed terms and be signed by or on behalf of both buyer and seller. In practice, you sign one copy of the contract and the buyer signs an identical copy, and your solicitors exchange them. From that moment you're both bound.

At exchange:

• The completion date is written into the contract. It's whatever you and the buyer have agreed through your solicitors.
• The buyer pays a deposit. The Council for Licensed Conveyancers says it's typically 10% of the purchase price. It counts towards the price.
• The sale stops being "subject to contract". You can't accept another offer, and the buyer can't renegotiate the price without your agreement.

Before exchange, GOV.UK is clear that neither side is under any legal obligation. An accepted offer, the agent's confirmation of the sale, or months of solicitors' work don't commit anyone. That's why gazumping and gazundering are possible in England and Wales.

What is completion?

Completion is when the sale actually happens. On the day:

1. The buyer's solicitor sends the rest of the money (the price minus the deposit) to your solicitor.
2. Your solicitor pays off your mortgage and any other loans secured on the home, the estate agent's fee and their own fee, and sends you what's left.
3. Your solicitor sends the buyer's solicitor the documents needed to transfer ownership, including the signed transfer deed (HM Land Registry's form TR1 for most sales), which is dated on the day of completion.
4. You hand over the keys, usually through the estate agent.

The buyer's solicitor then pays the buyer's Stamp Duty Land Tax (Land Transaction Tax in Wales) and registers the new owner with HM Land Registry. Those are the buyer's jobs, not yours.

Exchange and completion at a glance

	Exchange	Completion
What happens	Signed contracts are swapped and the completion date is fixed	The money is paid and the keys are handed over
Money	The buyer pays a deposit, typically 10%	The buyer pays the balance; your mortgage is paid off
Legal effect	Both sides are bound by the contract	Ownership passes to the buyer
Can you pull out?	Not without consequences	It's done
What you do	Sign the contract and transfer deed	Move out and hand over the keys

How long between exchange and completion?

There's no set gap. It's agreed between the buyer and seller, usually through their solicitors, and depends on the chain and how quickly everyone can move. GOV.UK's guide for buyers says completion is often around 2 to 4 weeks after exchange.

• A gap of a few weeks gives you a fixed moving date to book removals around, time to pack, and time for everyone in a chain to line up.
• Exchanging and completing on the same day is quicker, and can suit an empty house. The catch is that you can't be certain of the date until the day itself, so booking removals is a gamble.

Before exchange: what needs to be in place

Your solicitor won't exchange until:

• the buyer's solicitor has finished their searches and enquiries and is happy with the answers
• the buyer has a mortgage offer, if they need one, and the deposit ready
• you've signed the contract and agreed the completion date
• everyone in the chain is ready to exchange, if there's a chain
• you know roughly what it will take to pay off your mortgage, and that the price covers it

You'll usually sign the transfer deed at the same time, so it's ready for completion.

Between exchange and completion: a seller's checklist

GOV.UK's guide to selling suggests using the time between exchange and completion to:

• book removals (get more than one quote and check their insurance)
• tell your energy suppliers and broadband provider, and set up post redirection
• keep paying your mortgage until completion
• clear out anything you're not taking
• aim to be packed the day before

Your solicitor will ask your lender for a redemption statement, the exact figure needed to pay off your mortgage on the day, including any early repayment charge and interest. Keep your buildings insurance going until completion too.

On completion day

GOV.UK says completion often happens around lunchtime, so be moved out by then. Before you leave:

• remove all your belongings and rubbish, unless you've agreed otherwise (a buyer normally gets vacant possession, meaning an empty home with nobody living in it)
• leave everything you agreed to leave on the fixtures and fittings form
• take meter readings and photos of the meters, and tell your suppliers you've moved out
• leave the keys with the agent

Your solicitor will tell you when the money has arrived and the sale has completed. Only hand over keys once they've confirmed it. What happens on completion day goes through the day in more detail.

What can still go wrong

Before exchange

Quite a lot. The buyer's mortgage might fall through, their own sale might collapse, the survey might turn up problems, or either side might simply change their mind. The government's October 2025 consultation on home buying said around 1 in 3 transactions fail, citing research done for it in 2023. See what happens if a house sale falls through.

After exchange

Much less, but it does happen:

• Completion is delayed. Money can arrive late, often because something has held up another sale in the chain. Your contract sets out what happens if either side is late, so ask your solicitor what yours says.
• The buyer can't complete. If the buyer fails to complete, the seller may be able to keep the deposit, and depending on the contract may claim further losses.
• You can't complete. If you pull out or can't move out, you're in breach of contract. The buyer's deposit goes back to them and they could sue you for their costs and losses.
• Fraud. Criminals target this stage with fake emails about changed bank details. Check any change by phone, on a number you already know, before money moves either way.
• Damage to the house. A fire, flood or burst pipe before completion is the reason to keep your insurance until the money arrives.

After completion: tax and paperwork

If Capital Gains Tax is due on the sale, for example because the home was a second home or a rental, you must report it and pay the tax within 60 days of completion. Usually there's none to pay on a home that was your main home the whole time you owned it. Keep the completion statement from your solicitor for your records.

Will exchange and completion change?

Possibly, but not yet. In its June 2026 roadmap, the government said it plans to make sales binding earlier using conditional contracts, but only after it has introduced sales packs that give buyers key information before a home is listed. Both need new laws, which it will bring in when parliamentary time allows. For now it's encouraging voluntary reservation agreements, where one or both sides agree to pay compensation if they pull out.

Exchange and completion with a cash buyer

With no mortgage to arrange and no chain, a cash sale usually reaches exchange sooner, and the gap before completion can be as short as the two sides agree. If you sell to us, you choose the completion date: as little as 7 days, or a later date that suits you. The trade-off is price: our offer is below market value, and we explain how we worked it out. If you can wait and your home would sell well through an agent, the open market will usually get you more.