When and How You Pay Stamp Duty

Stamp duty is triggered on completion, paid within 14 days, and handled by your solicitor. Here is exactly when it is due, who pays it, and what happens at each stage of buying a property.

Stamp Duty Payment Timeline

Exchange

Contracts become binding

You are committed to buy, but no stamp duty is due yet

Day 0

Completion

Ownership transfers and your stamp duty liability begins

Day 1 to 14

Payment window

Your solicitor files the SDLT return and pays the tax

Day 14

Deadline

Late filing penalties start if the return is not submitted

After payment

Land Registry

The SDLT5 certificate lets the property be registered in your name

When stamp duty is due

Stamp duty is triggered on the effective date of the transaction. In an ordinary residential purchase that is your completion date, not the day you exchange contracts. Exchange is the point at which contracts become legally binding and you are committed to buy, but no tax is due and nothing is filed.

This distinction decides three practical things: which rates apply to your purchase, when the 14-day filing clock starts, and what you lose if the deal collapses. Each is covered below.

If rates change before you complete

You pay the rates in force on your completion date, not the rates that applied when you exchanged or made your offer. If a rate change lands during a long chain or a delayed conveyance, it is the completion-date rate that sets your bill. Check the current stamp duty rates before you commit to a completion date near a known change.

This cuts both ways. Buyers who exchanged before the 1 April 2025 threshold reversion but completed after it paid the post-April rates, because the completion date governed. A chain delay of a few days can therefore move your bill by thousands, which is why completion dates near an announced change are worth protecting.

Exchange vs completion: the effective date rule

The full rule is that the effective date is the earlier of completion or the date the contract is “substantially performed”. That second limb is set out in section 44 of the Finance Act 2003, and it is the reason the simple answer (“you pay on completion”) is not always the whole answer.

A contract is substantially performed when either of the following happens before completion:

You take possession of the property, for example by being given the keys early, moving in, or starting works under the contract.
You pay substantially all of the consideration, generally taken to mean around 90% or more of the purchase price.

The early-keys trap

If a seller lets you move in or start renovation between exchange and completion, the effective date can be pulled forward to that day. The 14-day filing clock then starts from the day you took possession, not from completion, and your return can be late before you or your solicitor have registered that anything changed. Tell your conveyancer before accepting early access, not after.

For the overwhelming majority of residential purchases none of this bites: you exchange, you complete a few weeks later, and completion is the effective date. It matters most in development agreements, agreements for lease and long-stop conditional contracts, which are covered in detail in options and development agreements.

Who pays stamp duty

The buyer pays stamp duty, never the seller. If you are selling a property, you pay no stamp duty on the sale itself, although capital gains tax can apply if the property was not your main residence.

In practice you rarely deal with HMRC yourself. Your solicitor or conveyancer normally prepares and submits the SDLT return and pays the tax on your behalf, using funds you provide as part of your completion statement. The money is collected from you before completion, not billed afterwards.

The responsibility stays with you

Your conveyancer files the return as your agent, but the legal obligation to notify HMRC and pay on time is the buyer’s. If a return is filed late or a relief is claimed incorrectly, HMRC pursues you, not the firm. It is worth checking that the return reflects your actual circumstances, particularly whether you have been treated as a first-time buyer or as owning an additional property, since those two fields move the bill more than any other.

Buying without a solicitor, for example a cash purchase of unregistered land, does not remove the duty to file. You can submit the return yourself, and the same 14-day deadline applies.

Where two or more people buy together, they are jointly liable for the whole amount, not for a share each. That also means the surcharge and first-time buyer tests look at every buyer: if one of you already owns a property, the additional property rates can apply to the entire purchase. See buying with a partner when only one of you is a first-time buyer.

How and when you pay

On completion day, ownership transfers and the 14-day clock starts. Your solicitor files the SDLT return and pays the tax to HMRC within 14 days of completion. You must file a return even if no tax is due, for example when first-time buyer relief reduces the bill to zero.

Late filing penalties

Miss the 14-day deadline and HMRC charges a £100 penalty, rising to £200 plus a £200 fixed penalty after 3 months, then tax-geared penalties and interest the longer it goes unpaid. See the full breakdown in the SDLT deadlines and penalties guide.

Buying soon? Get your stamp duty checked before you commit

A specialist can confirm the right figure and flag any reliefs you qualify for.

After you have paid

Once the return is filed and the tax paid, HMRC issues an SDLT5 certificate. This certificate is what allows the property to be registered in your name, so stamp duty and Land Registry registration are directly linked: no certificate, no registration.

Keep your SDLT5 certificate and return for at least 6 years. You will need the records if you ever claim a refund, for example if you sell a previous main residence within 36 months and reclaim the additional property surcharge through the refund claim process.

What to keep, and why

SDLT5 certificate, the proof the return was filed and the tax paid.
The submitted return itself, including the Unique Transaction Reference Number (UTRN), which HMRC asks for on any later amendment or refund claim.
The completion statement, which evidences the amount actually paid.
Evidence behind any relief claimed, for example first-time buyer status or a multiple dwellings apportionment. This is what HMRC asks for if it opens an enquiry.

If something on the return was wrong, you generally have 12 months from the filing date to amend it. That window runs from filing, not from completion, and it is the most common reason a legitimate refund is refused: the claim arrives after the amendment period has closed. Missing it does not always end the matter, but it turns a routine correction into a written appeal to HMRC with supporting evidence.

Scotland and Wales run to different clocks

The timeline above is the England and Northern Ireland one. The tax that applies depends on where the property is, not where you live, and the devolved taxes give you longer to file.

Where the property is	Tax	Authority	Deadline from effective date
England & Northern Ireland	SDLT	HMRC	14 days
Scotland	LBTT	Revenue Scotland	30 days
Wales	LTT	Welsh Revenue Authority	30 days

England cut its window from 30 days to 14 in March 2019; Scotland and Wales kept 30. If you are moving between nations, or buying in one while selling in another, the surcharge and refund rules differ too. See the Scotland and England relocation guide, or work the numbers with the LBTT calculator and LTT calculator.

Planning ahead

Budget for stamp duty as part of your total purchase costs, alongside your deposit, legal fees and survey. Because SDLT is charged in progressive bands, the price you offer can change your bill: nudging an offer just under a band threshold can save more than the few thousand pounds it appears to. See exactly how the bands work in how stamp duty is calculated, and how the cost affects your borrowing in stamp duty and mortgage affordability.

Stamp duty cannot usually be added to your mortgage in the way a deposit shortfall can, because lenders advance against the property value and the tax is payable in cash on completion. Plan for it as cash you need on the day.

If the purchase falls through

There is one small mercy in the timing rule. Because stamp duty is not due until the effective date, a sale that collapses before completion costs you no stamp duty at all. If you are gazumped or the chain breaks after you have paid for a survey and searches, those fees are lost, but no SDLT has been paid and none is owed. The exception is the substantial performance rule above: if you had already taken possession, the tax may have been triggered even though the sale never formally completed.

Common questions

Do you pay stamp duty on exchange or completion?

On completion. Exchange of contracts makes the purchase legally binding but triggers no stamp duty and no filing obligation. The only exception is where the contract is substantially performed first, for example by taking possession early, in which case the effective date moves to that earlier day.

When exactly do you have to pay stamp duty?

Within 14 days of completion in England and Northern Ireland, and within 30 days in Scotland (LBTT) and Wales (LTT). In practice your solicitor collects the money before completion and files shortly after, so the deadline rarely reaches you directly.

Do I need to file if no stamp duty is due?

Usually yes. A return is still required where relief reduces the bill to zero, such as first-time buyer relief, so a nil bill is not the same as no return. Some low-value transactions are not notifiable at all; the filing and payment guide sets out which.

Which rates apply if the rate changes between exchange and completion?

The rates in force on your completion date. Exchanging before a change does not lock in the old rates, which is why completion dates falling near an announced change are worth protecting in the contract.

What happens if my solicitor files late?

HMRC charges the buyer, not the firm: £100 up to 3 months late, £200 at 3 months and £300 at 12 months, plus interest on unpaid tax. You may have a claim against the firm, but the penalty notice comes to you. The full ladder is in the deadlines and penalties guide.

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