How long between exchange and completion?

Typically 1–4 weeks. Most buyers and sellers choose 2 weeks, which gives time for removals to be arranged, mail redirected, and utilities notified. Some transactions exchange and complete on the same day, though this requires careful coordination.

Can exchange happen over the phone?

Yes — and often does. Your solicitor and the seller's solicitor exchange verbally, confirming the contracts are identical and legally binding. This is followed by posting the signed contracts to each other. The verbal exchange is the binding moment.

What if I can't pay the deposit at exchange?

You need to have the deposit funds ready in your solicitor's client account before exchange can happen. If the funds aren't there, exchange can't proceed. Make sure you transfer your deposit funds to your solicitor's account a few days before the expected exchange date.

Can the seller change the completion date after exchange?

Not without your agreement. The completion date is fixed at exchange. Changing it requires both sides to agree. If the seller fails to complete on the agreed date without valid reason, you can serve notice and claim compensation.

What is a simultaneous exchange and completion?

Some transactions exchange and complete on the same day — this is common in cash purchases and some simple chains. It's faster but requires all paperwork and funds to be ready simultaneously, leaving no margin for last-minute issues.

Exchange of Contracts Explained

Exchange of contracts is the moment a house purchase stops being an arrangement held together by goodwill and becomes a legally binding contract. Before exchange, either side can walk away. After exchange, neither can — not without financial consequences.

What happens at exchange

Both solicitors have been working toward the same goal: a contract that both parties have approved, with all the legal details resolved. Once everything is agreed, exchange happens.

In practice: Your solicitor calls the seller's solicitor. Both confirm they hold identical, signed contracts. They agree the completion date. Both solicitors then date their copies of the contract simultaneously — this is the legally binding moment. The signed contracts are then posted to each other.

Your solicitor transfers your deposit to the seller's solicitor. In most transactions, this is 10% of the purchase price.

The deposit

The deposit at exchange is different from the deposit you've saved for your mortgage. Your mortgage deposit is what you put in to reduce your LTV — it could be 5%, 10%, or more. The exchange deposit is a contractual payment, usually 10% of the purchase price, paid at the time of exchange as part of the legal process.

If your mortgage deposit is only 5%, your solicitor may need to negotiate a reduced exchange deposit with the seller's solicitor — paying 5% at exchange with the balance on completion. This is common and usually agreed without difficulty.

What you can and cannot pull out from

Before exchange: Either party can withdraw at any time, for any reason, without penalty. You lose only what you've spent (survey, legal fees, mortgage application fees). This is frustrating but legal.

After exchange: The contract is binding. If you pull out:

You forfeit your full deposit
The seller can pursue you for damages if their losses exceed the deposit
Your mortgage offer lapses and may not be reinstated

If the seller pulls out after exchange, they must return your deposit in full, plus interest. You can also sue them for your losses, including legal costs, survey fees, and any price increase you suffered by having to buy a different property.

Setting the completion date

The completion date is agreed at exchange, written into the contract, and binding. Most buyers choose:

1–2 weeks: Tight but achievable. Removals can be booked at short notice, though popular dates go fast. Mail redirection needs minimum 5 working days' notice.

2–4 weeks: Most common. Enough time to arrange logistics without a prolonged wait in between. If you're in a chain, the whole chain needs to complete on the same day, so everyone has to agree.

Same-day (simultaneous exchange and completion): Only realistic for simple, chain-free purchases where everything is ready. No margin for error.

Buildings insurance starts at exchange

Your buildings insurance must be active from exchange of contracts — not completion. If something catastrophic happens to the property between exchange and completion (a fire, storm damage, flood), you are liable for the cost, not the seller. Their obligation to insure it ended at exchange.

Make sure your buildings insurance is in place and confirmed before exchange. Your solicitor should remind you; don't rely on them to do so.

This guide is information only. Dom does not provide financial, mortgage or legal advice. Always consult a qualified adviser for decisions specific to your circumstances.