Stamp Duty by Transaction Type
Different types of property transactions have different stamp duty rules and calculations. The tax base, rate structure, and available reliefs all vary depending on how a transaction is structured.
Choose Your Transaction Type
Select the type that matches your situation for a detailed guide, worked examples, and calculation rules.
Transaction Type Comparison
Not all transactions are taxed the same way. This table summarises the key differences between each transaction type under the post-April 2025 rules.
| Transaction Type | Tax Base | Nil-Rate Band | FTB Relief? | +5% Surcharge? | Filing Deadline |
|---|---|---|---|---|---|
| Standard Purchase | Full purchase price | £125,000 | Yes (up to £500k) | Yes (+5%) | 14 days from completion |
| Transfer of Equity | Chargeable consideration | £125,000 | Rarely | Sometimes | 14 days from effective date |
| Shared Ownership | Market value or staircasing | £125,000 | Yes, either route, if market value £500k or less | Generally no | 14 days from completion |
| Lease Transactions | NPV of rent + premium | £125,000 premium; NPV nil-rate £125,000 residential, £150,000 non-residential | Yes, on a qualifying residential lease premium | If residential | 14 days from effective date |
When Is Stamp Duty Triggered?
SDLT is not always triggered at completion. Understanding the “effective date” of a transaction is critical. Getting it wrong leads to penalties and interest.
Exchange of contracts
No, unless contracts are substantially performed
The clock starts only on completion in most residential cases
Substantial performance
Yes: SDLT triggered immediately
Occurs when you take possession, pay 90%+ of price, or a lease commences
Completion
Yes: 14-day deadline begins
Most common trigger point for residential purchases
Lease renewal/extension
Yes: new calculation required
Based on the NPV of rent over the new term
14-day rule: You must file your SDLT return and pay any tax due within 14 days of the effective date. Late filing carries an automatic £100 penalty, rising to £200 after 3 months, plus interest on unpaid tax.
Taking over part of a mortgage? That can mean stamp duty
A transfer can owe stamp duty even when no cash changes hands. Divorce transfers are usually exempt.
Common Transaction Scenarios
Real-world property situations often span multiple transaction types or involve unusual features. Here are some common scenarios and the key SDLT considerations for each.
Buying with a partner
Standard purchaseIf either buyer will still own another dwelling at the end of completion day, and it is not a main residence being replaced, the 5% additional dwelling surcharge applies to the whole purchase. If either buyer has ever owned a home, first-time buyer relief is lost.
Adding a partner to a mortgage
Transfer of equitySDLT applies if the incoming owner takes on a share of the mortgage. The chargeable consideration is their share of the debt taken on.
Buying via housing association
Shared ownershipYou can elect to pay SDLT on the full market value upfront or pay in stages as you staircase. For a first-time buyer on a property worth £300,000 or less, the election costs nothing and removes later staircasing SDLT; between £300,000 and £500,000 it depends on your figures.
Taking a new commercial lease
Lease transactionSDLT on leases is calculated on the net present value (NPV) of total rent over the lease term, with 1% payable on the NPV above £150,000.
Calculate Your Exact SDLT
Use our free calculator to get an instant SDLT estimate for any transaction type, buyer status, and property price.
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