Understanding Postponed Consideration and Instalment Payments in Land Transactions

SDLT on Deferred and Instalment Purchase Payments

For Stamp Duty Land Tax, the usual rule is that tax is worked out on the full price the buyer has agreed to pay for the property, even if some of that price is paid later or in instalments. Delaying payment does not usually reduce the amount of chargeable consideration, and future payments are not discounted just because they are due after completion or substantial performance.

• SDLT is generally charged on the full agreed purchase price, not just the amount paid on completion.
• If part of the price is postponed or paid by instalments, that does not by itself reduce the SDLT calculation.
• Future payments are not normally discounted to a lower present-day value for SDLT purposes.
• The key question is what the buyer is contractually required to pay under the transaction.
• This rule applies where the total price is fixed; different rules may apply if the amount is uncertain, contingent, or variable.
• For example, if a property costs £500,000 and £200,000 is paid later in instalments, SDLT is still based on £500,000.

Scroll down for the full analysis.

SDLT: postponed consideration and instalment payments

This page explains how Stamp Duty Land Tax treats consideration that is paid later rather than all at once. The key point is simple but important: SDLT is generally charged on the full amount the buyer has agreed to pay for the land transaction, even if some of that amount will only be paid in the future and even if it is paid by instalments.

What this rule is about

In some property transactions, the buyer does not pay the whole price on completion. Part of the price may be deferred to a later date, or the total may be split into instalments over time.

The legal issue is whether SDLT is worked out only on the amount actually paid when the transaction completes, or on the whole amount the buyer is obliged to pay under the agreement.

The rule in the source material addresses that point directly. It says that, for these purposes, the chargeable consideration is the full agreed amount, not just the amount handed over on completion or on substantial performance.

What the official source says

The official material states that where consideration is postponed or paid by instalments, the amount of chargeable consideration is the full amount of the agreed consideration payable at any time.

It also states that no discount is given simply because some payments are due in the future. In other words, future payments are not reduced to a present-day value for SDLT purposes under this rule.

What this means in practice

If a contract fixes the purchase price, but allows the buyer to pay part of it later, SDLT is still based on the whole agreed price.

This means:

• you do not calculate SDLT only on the amount paid on completion;
• you do not reduce later payments because they are delayed;
• you look at the total consideration the buyer has agreed to pay under the transaction.

This matters because buyers sometimes assume that deferred payment changes the SDLT base. Under this rule, it usually does not. A delayed payment timetable is not the same thing as a reduced amount of chargeable consideration.

The source also refers to substantial performance. That matters because SDLT can be triggered before formal completion in some cases. But even then, the relevant consideration is still the full agreed amount, not just what has physically been paid by that point.

How to analyse it

A sensible way to approach this issue is to ask the following questions:

• What is the total amount the buyer is contractually obliged to pay for the land transaction?
• Is that amount fixed and agreed, even if payment is deferred?
• Are payments simply being made by instalments, rather than the price being genuinely uncertain?
• Has completion occurred, or has the contract been substantially performed before completion?

If the total price is fixed, the starting point under this rule is that the whole amount is chargeable consideration.

The timing of payment does not itself reduce the SDLT amount. So a conveyancer or taxpayer should focus first on the legal amount payable under the contract, not on the cashflow timetable.

This rule should also be kept separate from other situations where consideration may be contingent, uncertain, variable, or subject to later adjustment. The source provided here is specifically about postponed consideration and instalments where there is an agreed amount to be paid.

Example

Illustration: a buyer agrees to buy land for £500,000. They pay £300,000 on completion and the remaining £200,000 in two instalments over the next two years.

Under the rule described in the source material, the chargeable consideration is £500,000, not £300,000 at completion and not a discounted figure reflecting the fact that £200,000 is paid later.

Why this can be difficult in practice

The main difficulty is identifying whether the arrangement is truly just deferred payment of a fixed price, or whether the future amount is in some way uncertain, contingent, or capable of change.

The source material here deals with the straightforward case: an agreed amount payable over time. It does not set out the treatment of more complex pricing mechanisms.

Another practical difficulty is that parties sometimes focus on when money changes hands rather than on what the contract requires. For SDLT, that can lead to the wrong result. The legal obligation to pay the full agreed consideration is what matters under this rule.

Key takeaways

• SDLT is based on the full agreed consideration, even if some of it is paid later.
• Paying by instalments does not, by itself, reduce the amount of chargeable consideration.
• No discount is applied simply because some payments are due in the future.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Understanding Postponed Consideration and Instalment Payments in Land Transactions

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