Exchange of Contracts vs Completion: What Is the Difference?
Two terms that cause persistent confusion in the home-buying process are exchange of contracts and completion. People sometimes use them interchangeably, but they are two distinct events separated by days or weeks — and the difference between them is legally and financially significant.
Exchange of Contracts
Exchange is the point at which the property transaction becomes legally binding. Both the buyer and the seller sign identical copies of the sale contract. Their respective solicitors then exchange these documents — traditionally by telephone, with each solicitor reading out the contract details to confirm they match, then posting the signed copies to each other.
At exchange, the buyer pays their deposit (typically 5–10% of the purchase price) to the seller's solicitor. A completion date is also fixed at this point, agreed by both parties in advance.
From exchange onwards, neither party can withdraw without serious financial penalty. If the buyer pulls out after exchange, they lose their deposit. If the seller pulls out, they must return the deposit and are liable to pay compensation equal to the deposit amount. This is what makes exchange the key milestone in the process — before it, everything is uncertain; after it, both sides are committed.
Completion
Completion is the day the property legally changes hands. On completion day, your solicitor transfers the balance of the purchase funds (the full purchase price minus the deposit already paid) to the seller's solicitor via bank transfer. Once the seller's solicitor confirms receipt, they authorise the release of keys — usually via the estate agent.
From this moment, you are the legal owner of the property. Your solicitor then handles the post-completion work: paying Stamp Duty Land Tax to HMRC (within 14 days of completion) and registering you as the new owner at HM Land Registry.
How Long Between Exchange and Completion?
The gap between exchange and completion is agreed by both parties at the time of exchange. One to four weeks is most common, though it can be as short as the same day (simultaneous exchange and completion) or as long as a few months. The most common arrangement is one to two weeks, which gives both parties time to arrange removals and make practical preparations.
Simultaneous exchange and completion is sometimes used in chain-free transactions where both parties want a quick conclusion, but it carries more risk as there is no buffer period between committing and actually moving.
What Happens if Something Goes Wrong Between Exchange and Completion?
Once contracts have been exchanged, the transaction is binding — but problems can still arise. If the seller's property is damaged between exchange and completion (a fire, for example), there are complex questions about who bears the risk, which is why buildings insurance should be in place from exchange. If a party defaults without a valid legal reason, the other party can enforce the contract through the courts and claim damages.
A Quick Reference Summary
| Exchange | Completion | |
|---|---|---|
| What happens | Contracts signed and swapped | Money transferred, keys released |
| Legally binding? | Yes — from this point | Yes — ownership transfers |
| Deposit paid | Yes (5–10%) | Balance paid |
| Can you pull out? | Only with financial penalty | No — it is done |
| When to arrange insurance | From exchange | Already in place |
This article is for general guidance only and reflects the conveyancing process in England and Wales. The legal process differs in Scotland. Always seek advice from a qualified solicitor for your individual circumstances.