The two key moments in a purchase
Most of the buying process, offer, survey, searches, mortgage and conveyancing, leads up to two pivotal events: exchange of contracts and completion.
Exchange is when the deal becomes legally binding. Before it, despite all the time and money spent, either party can walk away. This is why gazumping and last-minute withdrawals are possible right up until exchange. After exchange, you are committed: pulling out means losing your deposit and potentially being sued for the seller's losses.
Completion is when the property legally becomes yours. The remaining money changes hands, the keys are released, and you can move in. The period between exchange and completion is a short, defined window, often one to four weeks, that lets everyone prepare for moving day.
Exchange vs completion at a glance
What happens, and when, at each stage.
| Exchange of contracts | Completion | |
|---|---|---|
| Legally binding? | Yes, from this point | Already binding; ownership transfers |
| Money paid | Deposit (usually 10%) | Remaining balance + mortgage funds |
| Can you pull out? | Not without losing deposit | No |
| Get the keys? | No | Yes, on completion day |
| Insurance needed? | Buildings insurance must be in place | Continues |
Some transactions exchange and complete on the same day, removing the gap entirely.
What happens at exchange of contracts
1. Final checks complete
Searches, survey, mortgage offer and enquiries are all satisfied, and you've reviewed the contract.
2. Deposit ready
Your deposit (typically 10% of the purchase price) is with your solicitor, cleared and ready to transfer.
3. Completion date agreed
Both sides and the whole chain agree a completion date that works for everyone.
4. Solicitors exchange
The solicitors swap signed contracts (usually by phone, recorded) and the deal becomes legally binding.
What happens at completion
1. Funds transferred
Your solicitor sends the balance, including the mortgage advance, to the seller's solicitor.
2. Money confirmed received
Once the seller's solicitor confirms receipt, the sale legally completes.
3. Keys released
The estate agent or seller releases the keys, the home is now yours.
4. Post-completion admin
Your solicitor pays stamp duty and registers you as owner at HM Land Registry.
Get buildings insurance before exchange
From the moment you exchange contracts, you are usually responsible for the property even though you don't yet own it. Most lenders require buildings insurance to be in place from exchange, not completion. Arrange cover to start on your exchange date to avoid being uninsured if anything happens to the property before you move in.
Why the gap exists and how to avoid delays
The gap between exchange and completion gives everyone in the chain time to arrange removals, transfer large sums of money, request mortgage funds (lenders often need several days' notice) and co-ordinate moving dates. A typical gap is one to four weeks, though it can be longer by agreement, or zero if you exchange and complete on the same day.
Most delays come from chains, late mortgage funds, or outstanding legal enquiries. To keep things on track, respond quickly to your solicitor, have your deposit ready early, confirm your mortgage funds will be released in time, and stay in regular contact with your conveyancer and estate agent. The smoother the run-up to exchange, the calmer the move to completion.