Effective Date: When SDLT Liability Arises
The effective date is the date from which stamp duty liability arises and from which the 14-day filing deadline runs. It is usually the completion date, but it can be triggered earlier by substantial performance of the contract.
Last verified: April 2026 | Source: GOV.UK
Key Takeaways
- •The effective date is usually the completion date — when legal ownership transfers.
- •SDLT return must be filed and tax paid within 14 days of the effective date.
- •Substantial performance can bring the effective date forward — before formal completion.
- •The effective date is not the exchange date — SDLT is not triggered at exchange.
- •Wales LTT has a 30-day deadline from the effective date (vs SDLT's 14 days).
In this article
What Is the Effective Date
The effective date is the legal trigger point for SDLT liability. It is the date from which:
- •SDLT is due
- •The 14-day SDLT return filing deadline starts
- •Ownership for higher rates purposes is assessed
In most residential purchases, the effective date is the same as the completion date. SDLT rates in force on that date apply — if rates change before completion, the new rates apply.
Effective Date vs Completion Date
In the vast majority of property transactions, the effective date and the completion date are the same day. Completion is when the purchase price is paid in full and legal title transfers.
The distinction only matters when something unusual happens — specifically, when the contract is substantially performed before formal legal completion.
Effective Date vs Exchange Date
Exchange of contracts does not trigger SDLT. Exchange creates a legally binding agreement but does not transfer legal title or trigger tax liability. SDLT is not due at exchange.
Typical property transaction timeline
Exchange of contracts
Legally binding — no SDLT triggered
Completion (effective date)
Legal title transfers — SDLT liability arises
14 days later
SDLT return and payment deadline
Substantial Performance
A contract is "substantially performed" before completion if any of the following occur before formal legal completion:
- •The buyer takes possession of the property (including moving in)
- •The buyer begins paying rent under the contract
- •The buyer pays a substantial portion of the purchase price (generally defined as 90% or more)
When substantial performance occurs, the effective date moves to that earlier date. A further SDLT return may also be required at formal completion if additional consideration is then paid.
Linked Transactions
In linked transactions, each individual transaction has its own effective date. A separate SDLT return must be filed within 14 days of each effective date. However, SDLT on each is calculated by reference to the total consideration across all linked transactions.
Wales: LTT Difference
In Wales, the equivalent concept under LTT is also called the effective date and works the same way. However, the LTT filing and payment deadline is 30 days from the effective date — not 14 days.
Official Government Source
For official SDLT guidance, including the effective date rules:
Stamp Duty Land Tax — GOV.UKFrequently Asked Questions
What is the effective date for stamp duty?
The effective date is the date on which SDLT liability arises. It is usually the completion date — the date when legal ownership transfers and the purchase price is paid in full. HMRC requires the SDLT return to be filed and tax paid within 14 days of the effective date.
Can the effective date be before completion?
Yes. 'Substantial performance' can trigger the effective date before formal legal completion. This typically occurs when the buyer takes possession of the property, starts paying rent under the contract, or pays a substantial part of the purchase price before contracts are formally completed.
Is the effective date the same as the exchange date?
No. Exchange of contracts creates a legally binding agreement but does not transfer legal title. The effective date for SDLT is typically completion — not exchange. SDLT is not triggered at exchange.
In this article
Emma Richardson, MRICS
Chartered Surveyor & Property Tax Specialist
Emma Richardson is a RICS-qualified Chartered Surveyor with over 12 years of experience in UK property taxation. She founded Calculate My Stamp Duty UK to help buyers understand the complex world of property transaction taxes.