Lease Extension Stamp Duty: Extending Your Leasehold Term
SDLT on residential and commercial lease extensions — statutory vs voluntary routes, marriage value, ground rent changes, and a worked example.
Key Takeaways
- Extending a lease counts as granting a new lease for SDLT purposes — SDLT applies to the premium paid to the freeholder
- Statutory extensions under the Leasehold Reform Act 1993 reduce ground rent to peppercorn, eliminating any NPV element
- Informal (voluntary) extensions may retain ongoing ground rent, requiring an NPV calculation in addition to premium SDLT
- Marriage value applies to leases under 80 years and is shared 50/50 between leaseholder and freeholder — it affects the premium size not the SDLT rates
- Qualifying leaseholders must have owned for at least 2 years before they can use statutory extension rights under the 1993 Act
- SDLT is payable on the premium within 14 days of the effective date of the new lease
- A leasehold property with under 80 years unexpired is sometimes called a "short lease" — marriage value makes extensions significantly more expensive
- Leasehold Reform Act 2024 will eventually allow extensions of up to 990 years but implementation is phased
In this article
How Lease Extension SDLT Works
When you extend a lease — whether a flat, house, or commercial property — the law treats the extension as the grant of a new lease. This means SDLT can apply to the transaction, specifically to the premium (the money you pay the freeholder for the extension) and, in some cases, to the Net Present Value of any ongoing ground rent.
The SDLT treatment differs significantly depending on whether you use the statutory route under the Leasehold Reform Act 1993 or negotiate a voluntary extension directly with the landlord. Our leasehold stamp duty complete guide provides broader context on all leasehold transactions.
Two Routes, Different SDLT Outcomes
Statutory extension: Ground rent drops to peppercorn. Only the premium is taxed at standard residential rates.
Voluntary extension: Terms are negotiated. If ground rent continues, NPV calculation also applies alongside the premium SDLT.
Statutory Lease Extensions Under the Leasehold Reform Act 1993
The Leasehold Reform, Housing and Urban Development Act 1993 gives qualifying leaseholders of flats the statutory right to extend their lease by 90 years on top of the current unexpired term (so an 80-year lease becomes 170 years). The Act specifies that upon extension, the ground rent reduces to a peppercorn — effectively zero.
For SDLT purposes, a statutory extension is straightforward:
- Premium: SDLT applies at standard residential rates on the premium paid to the freeholder. Rates are 0% on the first £125,000, 2% from £125,001 to £250,000, and 5% on the portion above £250,000.
- Ground rent NPV: Since the ground rent reduces to peppercorn, there is no NPV to tax. The rent element of SDLT is zero.
The statutory process requires the leaseholder to serve an initial notice on the freeholder, negotiate the premium, then proceed to a formal Deed of Variation (or new lease) to effect the extension.
Qualifying Tenants Under the 1993 Act
Not all leaseholders can use the statutory route. To qualify under the Leasehold Reform Act 1993, you must meet these conditions:
| Requirement | Detail |
|---|---|
| Ownership period | Must have owned the flat for at least 2 years |
| Long lease | Original lease granted for more than 21 years |
| Property type | Must be a flat (not a house — houses use the 1967 Act) |
| Low rent test | No longer strictly applicable post-2002 reforms |
| Business use | Property must not be used for business purposes |
The Leasehold Reform Act 2024 (when fully implemented) will extend these rights and allow extensions of up to 990 years rather than the 90-year addition. The peppercorn ground rent requirement will continue to apply.
Voluntary (Informal) Lease Extensions
A voluntary or informal extension is negotiated directly with the freeholder outside the statutory process. The terms — including the premium, new lease length, and ground rent provisions — are entirely a matter of agreement between the parties.
The SDLT implications of a voluntary extension depend on what is agreed:
Scenario A: Premium only, peppercorn rent
Ground rent is reduced to peppercorn as part of the deal. SDLT applies only to the premium at standard residential rates. Identical outcome to statutory extension.
Scenario B: Premium plus ongoing ground rent
The new extended lease retains a ground rent. SDLT applies to the premium (at standard rates) AND to the NPV of the new ground rent (at 0%/1% residential NPV rates). Both are calculated separately and added together.
Scenario C: No premium, just ground rent continuation
Rare. SDLT applies only to the NPV of the new/extended ground rent obligation. If NPV is below £125,000 (which is common for modest ground rents), SDLT is zero.
Ground Rent Changes on Extension
The Leasehold Reform (Ground Rent) Act 2022 (effective 30 June 2022) prohibits ground rent above a peppercorn on new residential leases. This means any residential lease extended after this date must, by law, have peppercorn ground rent if it is a new regulated lease.
For existing leases extended under the statutory route, the 1993 Act already required ground rent to reduce to peppercorn regardless of the 2022 Act. For informal extensions of post-June 2022 leases, the 2022 Act restricts the landlord from charging above peppercorn.
For pre-2022 leases being extended informally, the ground rent position depends on negotiation. Some freeholders agree to reduce to peppercorn as part of the deal; others retain the existing ground rent on the extended term. Where ground rent is retained, an NPV calculation applies. See our ground rent NPV calculation guide for the detailed formula.
Marriage Value and Its Effect on the Premium
Marriage value is the additional value created when a short lease (under 80 years) is extended. When a lease has fewer than 80 years unexpired, the value of the leasehold interest drops noticeably because mortgage lenders become increasingly reluctant to lend against short leases. The act of extending adds disproportionate value.
Under the Leasehold Reform Act 1993, marriage value is calculated as:
The freeholder is entitled to 50% of the marriage value as part of the statutory premium calculation. For leases with more than 80 years unexpired, marriage value is assumed to be zero (no uplift element in the premium).
Marriage value increases the premium you pay. A higher premium means more SDLT — but the rates themselves do not change. The 0%/2%/5% standard residential rates still apply to whatever premium results from the valuation (including marriage value element).
Practical Tip
If your lease has between 81 and 85 years remaining, act sooner rather than later. Once it drops below 80 years, marriage value kicks in and the premium (and therefore your SDLT) will be materially higher. Use our leasehold extension calculator to estimate the premium.
Commercial Lease Extensions
Commercial tenants typically renew or extend leases under the Landlord and Tenant Act 1954 (which gives most business tenants the right to renew at market rent). For SDLT purposes, a commercial lease extension is treated as a grant of a new lease.
SDLT on commercial lease extensions applies to:
- Premium (if any): at standard non-residential rates (0%/2%/5%)
- NPV of rent: at commercial NPV rates (0% up to £150,000 NPV, 1% on £150,001-£5m, 2% above)
- Overlap relief: credit for SDLT paid on the previous lease for any period covered by both
Unlike residential leases, there is no statutory requirement for commercial ground rent to reduce. The rent on a commercial extension is typically market rent, potentially higher than under the original lease. See our commercial lease renewal guide for more detail on the overlap relief mechanism.
Worked Example: Extending an 80-Year Lease to 990 Years
This example illustrates a common scenario where a flat owner with an 80-year lease seeks a statutory extension, taking the lease to 170 years (80 + 90 years under the 1993 Act) — or 990 years under the forthcoming 2024 Act reforms. We use 170 years as the current law, with £30,000 as the agreed premium.
Extension Details
- • Current lease remaining: 80 years
- • Extension type: Statutory (Leasehold Reform Act 1993)
- • New lease term: 170 years (80 + 90)
- • Agreed premium: £30,000
- • New ground rent: Peppercorn (£0)
Step 1: SDLT on Premium (£30,000)
The £30,000 premium falls within the 0% band (below £125,000).
Step 2: SDLT on Ground Rent NPV
Ground rent is peppercorn (zero), so NPV = £0.
Total SDLT: £0
Note: Even though no SDLT is due, a land transaction return (SDLT1) may still be required if the premium or NPV triggered SDLT. Confirm with your solicitor whether a return is needed.
Variation: Extension with Retained Ground Rent
If the freeholder insists on retaining a £500/year ground rent on the extended term:
- • Premium: £30,000 (SDLT = £0, below £125,000)
- • Ground rent: £500/year for 170 years
NPV of £500/year for 170 years at 3.5%:
NPV of £14,285 is below the £125,000 residential threshold.
Even with retained ground rent, modest annual amounts rarely exceed the NPV threshold on typical residential leases.
Timing and Filing Requirements
The SDLT return and any tax due must be submitted within 14 days of the effective date of the lease extension. The effective date is typically the date the extension deed is completed and the new lease takes effect.
Your conveyancing solicitor will handle the SDLT return as part of the lease extension process. Even where SDLT is zero (common for statutory extensions with peppercorn rent and low premiums), a return may be required if the transaction meets the land transaction filing threshold.
The lease extension must also be registered at HM Land Registry. Your solicitor will handle this simultaneously with the SDLT return.
Calculate Your Lease Extension SDLT
Use our calculator to estimate the stamp duty on your lease extension.
Lease Details
Current market value with existing lease
This is a simplified estimate. The actual lease extension premium is calculated using the Leasehold Reform Act formula. Get a professional RICS valuation for accurate figures.
Extension Cost
Estimated Premium
£750
Marriage Value
£0
Ground Rent Component
£750
Estimated Total Cost
£3,250
Includes premium + legal fees (£2,000) + valuation (£500)
Cost Breakdown
Property Value Analysis
Cost Breakdown
Disclaimer: This tool does not constitute financial advice. We do not recommend taking actions based solely on these results. The calculator makes assumptions and results may be inaccurate due to changes in government policy, interest rates, or personal circumstances. You use this information at your own risk. We can't guarantee to be perfect, so do note you use the information at your own risk and we can't accept liability if things go wrong. For official guidance, visit Gov UK.
Frequently Asked Questions
Does buying a flat with a short lease affect SDLT?
No. SDLT on the purchase of a flat (assignment of existing lease) is based on the purchase price, not the lease length. However, a short lease makes the flat harder to mortgage and worth less, so the purchase price will be lower — which actually reduces SDLT.
Can I extend a lease I bought recently?
For a statutory extension under the 1993 Act, you must have owned the flat for at least 2 years before serving your initial notice on the freeholder. You can negotiate a voluntary extension at any time — there is no ownership period requirement for informal extensions.
Is lease extension stamp duty different from the purchase SDLT?
Yes. When you buy the flat, SDLT is on the purchase price using standard residential rates. When you extend the lease, SDLT is on the premium using the same rates — but the premium is typically much less than the purchase price. The ground rent NPV element is an additional calculation that rarely produces SDLT where rent is peppercorn.
Does the additional 3% SDLT surcharge apply to lease extensions?
The additional 3% higher rates surcharge applies to acquisitions of dwellings where the buyer already owns another property. A lease extension is not an acquisition in the same sense — you already own the leasehold interest. The higher rates do not apply to lease extensions. However, if you were purchasing a second flat by way of new lease grant (not extension), the 3% surcharge could apply.
What if I extend the lease as part of buying the flat?
Where a seller extends the lease immediately before or as part of a sale, SDLT is paid by the seller on the extension premium and by the buyer on the purchase price. These are two separate transactions. If you are the buyer acquiring a newly extended lease, SDLT is on your purchase price only — the seller's extension premium is their SDLT liability.
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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 Stamp Duty Calculator to help buyers understand the complex world of property transaction taxes.